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. 2024 Jul 27;30(6):706–750. doi: 10.1093/humupd/dmae023

Table 3.

Animal studies.

Reference Sample size Intervention Assay methods Results Conclusion Relevance to fibrosis
Akarca-Dizakar et al., 2022; The therapeutic effects of coenzyme Q10 (CoQ10) on surgically induced endometriosis in Sprague Dawley rats (Akarca-Dizakar et al., 2022) N = 27 (7, 6, 7, 7); rat. Autologous uterine tissue transplantation CoQ10 50 or 100 mg/kg, Buserelin (GnRH agonist) Lesion size, Masson stain, toluidine stain, IHC, ELISA Significant decrease of lesion size and adhesion scores before and after treatment in low and high dose CoQ10 and Buserelin groups. Mast cell number decreased in all treatment groups and collagen density increased CoQ10 treatment decreased histopathological effects of endometriosis implants without considerable side effects Anti-oxidant CoQ10 treatment as well as GnRH agonist treatment decreased lesion size and increased collagen density
Arangia et al., 2023; Fisetin, a natural polyphenol, ameliorates endometriosis modulating mast cells derived NLRP-3 inflammasome pathway and oxidative stress (Arangia et al., 2023) N = 36 exclusive donors (3 * 12); rat. Intraperitoneal injected uterine donor tissue Fisetin 40 mg/kg Lesion size, Masson stain, toluidine stain, IHC, WB, ELISA Lesion size, mast cell infiltration, and activation, the extent of collagen fibers, α-SMA, TGF-β and NLRP-3 inflammasome expression, and markers for oxidative stress were all reduced in fisetin treatment group compared to vehicle controls Mast cell activation and the NLRP-3 inflammasome pathway and oxidative stress stimulate endometriosis development and fibrosis, fisetin can alter these signaling pathways and thereby inhibit endometriosis formation Fisetin can reduce fibrosis via inhibiting mast cell activation and oxidative stress pathways
Buigues et al., 2018; Evaluation of PAI-1 in endometriosis using a homologous immunocompetent mouse model (Buigues et al., 2018) N = 56 (2 * 7, donors); mice. subcutaneous transplantation of donor uterine tissue PAI-039 (PAI-1 inhibitor) 10 mg/kg or control; oral, once daily Lesion size, Masson stain, IHC Decreased lesion size in the treatment group. Collagen surrounds lesions in the treatment and control groups, no difference in the stained area. No differences in immune cell infiltration Plasminogen activator inhibitor-1 overexpression stimulates angiogenic demands of endometriotic lesions. PAI-1 inhibition with PAI-039 decreases lesion size. No clear effect on the amount of collagen PAI-1 increases endometriotic lesion characteristics but does not influence fibrosis
Cao et al., 2019; Plasma high mobility group box 1 (HMGB1), osteopontin (OPN), and hyaluronic acid (HA) as admissible biomarkers for endometriosis (Cao et al., 2019)

  • N = 32 (3 * 8, 8 donors); mice.

  • Intraperitoneal injection of donor uterine tissue

 None HE, Masson stain, IHC, ELISA Lesion size and fibrosis were progressive over time, and hotplate latency decreased. Plasma HMGB1, OPN, and HA correlated with lesional progression and fibrosis HMGB1, OPN, and HA are potential biomarkers for endometriosis The correlation between fibrosis and plasma levels of HMGB1, OPN, and HA shows potential as biomarkers for endometriosis
Chen et al., 2021; Preoperative and perioperative intervention reduces the risk of recurrence of endometriosis in mice caused by either incomplete excision or spillage and dissemination (Chen et al., 2021) N = 171 (16, 5 * 10, 4 * 12, donors); mice. Intraperitoneal injection of donor uterine tissue Ketorolac 7.5 mg/kg before, saline after. Aprepitant 25 mg/kg before and after. Propanolol 10 mg/kg + andrographolide 180 mg/kg before and after Lesion size, Masson stain, IHC Spill experiment: E-cadherin, PR-B were elevated in intervention groups, α-SMA, p-p65, VEGF, ADRB2 reduced, fibrosis reduced. Weight correlated pos with α-SMA and fibrosis. Hotplate latency correlated neg with α-SMA and fibrosis. α-SMA Pre- and perioperative administration of ketorelac, propanolol + andrographolide and aprepitant inhibits outgrowth of endometriotic lesions after spillage or incomplete excision, in combination with reduced fibrogenesis and improved pain behavior in the lesions in a mouse model Pre- and perioperative interventions could be used to decrease risk of endometriosis recurrence including a inhibiting effect on fibrosis and improved pain behavior
Incomplete excision experiment: E-cadherin, PR-B elevated in the intervention group, α-SMA, p-p65, VEGF, ADRB2 reduced in the intervention group. Fibrosis reduced. lesion weight correlated pos with α-SMA and fibrosis. Hotplate latency correlated negatively with α-SMA and fibrosis
Cordaro et al., 2021; Hidrox and endometriosis: biochemical evaluation of oxidative stress and pain (Cordaro et al., 2021) N = 20 (3 * 5, donors); rats. Intraperitoneal injection of donor uterine tissue Hidrox (hydroxytyrosol concentrate) 10 mg/kg by gavage daily from day 7 to 14 Lesion size, Masson stain, IHC, hotplate latency, ROS levels Reduced lesion size, collagen, α-SMA, Ki67, and BCL-2, increased Bax in Hidrox treatment group. Longer hotplate latency in the treatment group Hidrox, as a strong anti-inflammatory and anti-oxidant agent, reduces endometriosis lesion size, inflammation, and fibrosis. It restores oxidative balance in hippocampus and relieves endometriosis-associated pain Hidrox reduced fibrosis in endometriosis via oxidative stress decrease
Daftary et al., 2013; A novel role of the Sp/KLF transcription factor KLF11 in arresting the progression of endometriosis (Daftary et al., 2013) N = 21 (3 * 7); mice. Autologous uterine tissue transplantation Klf 11 knockout, Klf 9 knockout controls, wild-type controls Lesion size, Masson stain, RT-qPCR Klf 11−/− mice had larger lesions, more fibrosis, and higher collagen I expression and deposition versus Klf 9−/− and wild-type controls Klf 11 seems to have a protective role in the pathologic process of endometriosis Klf 11 protective role in endometriosis includes fibrosis and other endometriotic lesion characteristics
Delaney et al., 2016; KLF10 mediated epigenetic dysregulation of epithelial CD40/CD154 promotes endometriosis (Delaney et al., 2016) N = 21 (3 * 7); mice. Autologous uterine tissue transplantation Klf 10 knockout, Klf 11 knockout controls, wild-type controls Lesion size, Masson stain, RT-qPCR, IHC Klf10−/− mice had >2-fold increase in lesion size, lesions associated with polymorphonuclear cell infiltrate. Fibrosis score slightly elevated in Klf10−/− mouse versus wild-type, but evident decrease versus Klf11−/− Klf10 knockout in mice resulted in prominent inflammation and increased lesion size, but only slightly increase in fibrosis Klf 10 protective role in endometriosis includes inflammation, but not fibrosis
Di Paola et al., 2016; Co-micronized palmitoylethanolamide/polydatin (mPEA/PLD) treatment causes endometriotic lesion regression in a rodent model of surgically induced endometriosis (Di Paola et al., 2016) N = 20 (2 * 10); rat. Autologous uterine tissue transplantation m(PEA/PLD) 10 mg/kg daily or vehicle control HE, Masson, Toluidine blue. IHC. WB. Tail-Fick method, Hot plate latency m(PEA/PLD) treated rats had smaller cysts, less inflammatory cell infiltration and edema, lower pain behavior scores, and larger fibrotic area m(PEA/PLD) treatment decreased lesion size and increased fibrosis. It reduced inflammatory and angiogenic parameters and pain behavior Fibrosis increased by m(PEA/PLD) treatment, whereas other lesions characteristically improved
Ding et al., 2019; Scutellarin suppresses platelet aggregation and stalls lesional progression in mouse with induced endometriosis (Ding et al., 2019) N = 27 (3 * 9); mice. Intraperitoneal injection of donor uterine tissue Scutellarin low dose 7,5 mg/kg, high dose 15 mg/kg every two days IV or vehicle control HE, Masson, IHC, hotplate latency, peripheral platelet levels Scutellarin reduced platelet activation, lesion weight, fibrosis, α-SMA, and collagen I expression and increased hotplate latency. Lesion weight correlated positively with fibrosis and α-SMA Scutellarin is efficacious as a treatment for endometriosis by suppressing platelet aggregation, inhibiting proliferation, angiogenesis, and fibrogenesis, resulting in reduced lesion size and improved pain behavior in mice Fibrotic markers correlate with lesion weight and platelet-targeted therapy reduced fibrosis
Dogan et al., 2023; The effect of rituximab on experimental endometriosis model in rats (Dogan et al., 2023) N = 24 (12, 11); rat. Autologous uterine tissue transplantation Rituximab 10 mg/kg Lesion size, HE, Masson stain, IHC Implant size was decreased in the rituximab treatment group versus controls, with no difference in HE histology score and fibrosis scores between groups Rituximab reduced lesion size and therefore is a potential therapeutic agent for endometriosis Rituximab did not reduce fibrosis and slightly reduced lesion size
Dogru et al., 2017; Effect of amygdalin on the treatment and recurrence of endometriosis in an experimental rat study (Dogru et al., 2017) N = 30 (3 * 10); rat. Autologous uterine tissue transplantation Amygdalin 5 mg/kg once a week IP, leuprolide 0,0375 mg/kg SC or saline control Lesion size, Masson stain Lesion size was smaller in both treatment groups other groups compared to control. No differences in fibrotic area Amygdalin is superior to leuprolide in reducing endometriosis implant size. No clear effect from any treatment on fibrosis scores Fibrosis not reduced by amygdalin or leuprolide treatment, lesion size was reduced
Duan et al., 2018; The M2a macrophage subset may be critically involved in the fibrogenesis of endometriosis in mice (Duan et al., 2018) N = 115 (5 * 6, 2 * 6, 4 * 7, donors); mice. Intraperitoneal injection of donor uterine tissue Macrophage depletion by diphtheria toxin in CD11b-DTR mice. Ex vivo differentiated macrophage IV administration Lesion size, Masson stain, IHC, hotplate latency M2 macrophage infiltration and fibrotic markers increased over time. Macrophage depletion reduced fibrosis, lesion weight, and pain behavior. M2a, but not M1 or M2c macrophage suppletion after depletion increased fibrosis M2a, but not M1 or M2c, macrophages are critically involved in fibrogenesis in endometriosis through promoting EMT, FMT, SMM, and production of pro-fibrotic mediators such as TGF-β1 M2 macrophages are involved in fibrogenesis
Genovese et al., 2022; Molecular and biochemical mechanism of cannabidiol in the management of the inflammatory and oxidative processes associated with endometriosis (Genovese et al., 2022) N = 30 (3 * 10); rat. Intraperitoneal injection of donor uterine tissue Cannabidiol (CBD) 10 mg/kg Lesion size, ultrasound, HE, Masson stain, IHC, WB, open field, hotplate latency, plus maze and acetic-acid induced contractions test CBD treatment reduced lesion size, markers of oxidative stress, the extent of fibrosis, expression of MMP-9, TGF-β, and nerve growth factor, mast cell infiltration, and pain behavior Anti-oxidant, anti-fibrotic, and anti-inflammatory activities of cannabidiol can be useful to stop the development of endometriosis Cannabidiol reduced fibrosis development in endometriosis
Grande et al., 2023; Host immunity and KLF11 deficiency together promote fibrosis in a mouse model of endometriosis (Grande et al., 2023) N = 30 (3 * 10); mice. Autologous or donor uterine tissue transplantation KLF11−/−, KLF10−/− knockout or wild-type (WT), HATI treatment (auto-transplantation). LacZ-KLF11−/−, Smad3−/+ (donor transplantation) HE, Masson stain, IHC, RT-qPCR KLF10−/− and KLF11−/− showed lower adhesion scores than WT after 1, 2, and 3 weeks post-implant, KLF11−/− showed highest scores, in all groups, but most in KLF11−/−, scores progressive over time. HATI treatment reduced scores in KLF11−/− but not affected WT or KLF10−/−. Collagen extent mirrors adhesion scores in all mice. Smad3 controlled LacZ-KLF11−/− donor implants leads to ectopic antigen expression and enhanced fibrosis. Fibrogenesis was attenuated in Smad3 knockout transplants

  • KLF11 and TGF-βR signaling are important mechanisms in fibrogenesis in endometriosis.

  • KLF11 knockout and a triggered immune response to implants triggers extensive fibrosis

 KLF11 is protective against fibrosis via TGF-β signaling
Guo et al., 2015; P-selectin as a potential therapeutic target for endometriosis (Guo et al., 2015a) N = 64 (6 * 8, 2 * 8); mice. Autologous or donor uterine tissue transplantation P-selectin knockout in donor or recipients; Platelet transfusion; P-selection-Fc treatment Lesion size, Masson stain, IHC, hotplate latency P-selectin knockout (donor and/or recipient) and P-selection-Fc reduced lesion size, platelet aggregation, macrophage infiltration, and fibrotic markers. P-selection-Fc treatment improved hotplate latency P-selectin knockout or blocking treatment reduced endometriotic implant size and reduced fibrotic markers, TGFB, platelet aggregation, and neovascularization Platelet activation is a potential fibrosis-based target for endometriosis
Guo et al., 2016; Anti-platelet therapy is efficacious in treating endometriosis induced in mouse (Guo et al., 2016) N = 79 (3 * 10, 4 * 8, donors); mice. Autologous uterine tissue transplantation or intraperitoneal injection of donor uterine tissue Ozagrel 15 or 30 µg/g daily IP or control; IgG-mediated macrophage and/or platelet depletion Lesion size, Masson stain, IHC, hotplate latency Ozagrel reduced lesion size, improved hyperalgesia, and reduced fibrotic markers. Platelet and/or macrophage depletion reduced lesion size, platelet and macrophage infiltration in lesions and fibrotic markers Anti-platelet interventions reduce lesion size and fibrotic markers and have the potential as a treatment for endometriosis Platelet activation is a potential fibrosis-based target for endometriosis
Guo et al., 2021; NLRP3 inflammasome activation of mast cells by estrogen via nuclear-initiated signaling pathway contributes to the development of endometriosis (Guo et al., 2021) N = 24 (4 * 8); mice. Intraperitoneal injection of donor uterine tissue NLRP3 inhibitor CY-09 2,5 mg/kg daily Lesion size, Masson stain Il-1β levels in peritoneal fluid were elevated in untreated endometriosis vs healthy controls., but reduced in NLRP3 inhibitor treatment. NLRP3 inhibitor reduced weight, size, and fibrotic area of lesions at 14 and 21 days Estrogen can promote mast-cell-derived NLRP3 activation and IL-1β secretion, which can lead to development of endometriosis. In vivo mouse experiment showed decreased fibrotic changes after NLRP3 inhibitor treatment NLRP3 inhibition has the potential as a fibrosis target for endometriosis
Hao et al., 2021; Reduced vagal tone in women with endometriosis and auricular vagus nerve stimulation as a potential therapeutic approach (Hao et al., 2021) N = 90 (3 * 10, 3 * 10, 3 * 10); mice. Intraperitoneal injection of donor uterine tissue Nervus vagotomy, vagal nerve stimulation (VNS) before or after endometriosis induction Lesion size, Masson stain, IHC, hotplate latency Vagotomy increased, VNS (both before and after induction of endometriosis) decreased lesion size, EMT and FMT markers and extent of fibrosis. Hotplate latency decreased after vagotomy and increased after VNS A sympathetic domination of the autonomic nervous system may have a role in endometriosis. Vagotomy as a model for reduced vagal activity accelerates endometriosis progression and fibrogenesis. Auricular vagal stimulation decelerates endometriosis progression and fibrogenesis Sympathetic domination of the autonomic nervous system may stimulate endometriosis, also fibrogenesis
Hao et al., 2022; Activation of α7 nicotinic acetylcholine receptor retards the development of endometriosis (Hao et al., 2022) N = 60 (3 * 8, 2 *8 , 20 donors); mice. Intraperitoneal injection of donor uterine tissue PNU-282987 (α7nAChR agonist), methyllycaconitine citrate (MLA - α7nAChR antagonist) Lesion size, HE, Masson stain, IHC, hotplate latency Early PNU treatment reduced lesion size, α-SMA expression, and extent of fibrosis, with no differences between MLA and control group. PNU treatment after the establishment of deep endometriosis reduced lesion size, EMT marker expression and fibrosis, and prolonged latency time compared to controls Activation of α7nAChR by agonist treatment impeded lesion development, probably via EMT and FMT hindrance. α7nAChR agonist treatment reversed lesion development and fibrosis in a deep endometriosis model Activation of α7 nicotinic acetylcholine receptor treated endometriosis and fibrosis successfully in mice
HayaShi et al., 2020; Novel ovarian endometriosis model causes infertility via iron-mediated oxidative stress in mice (HayaShi et al., 2020) N = 83 (24 recipients, controls, donors); mice. Transplantation of donor uterine tissue in ovarian bursa None Lesion size, HE, Masson stain, Berlin blue stain, IHC Fibrosis was progressive over time, iron accumulation was present in model, accompanied by oxidative stress. Expression of FSH receptor and number of offspring were reduced in model animals Successful establishment of ovarian endometrioma model. Model accompanies fibrosis and leads to iron-mediated oxidative stress and reduced fertilization Increased fibrosis was accompanied by iron accumulation and decreased fertility
Herington et al., 2013; Dietary fish oil supplementation inhibits the formation of endometriosis-associated adhesions in a chimeric mouse model (Herington et al., 2013)

  • N = 45 (19, 15, 11); mice.

  • Intraperitoneal injection of human endometrium

 Dietary fish oil: none, 5% of diet, 10% of diet Lesion size, HE, Masson stain, IHC, macroscopic adhesion score Lesion size, adhesion score, extent of fibrosis, and immune cell infiltration were smaller in high and low-dose fish oil suppletion groups Anti-inflammatory dietary interventions like fish oil supplementation reduce endometriotic implant size, visual adhesions, and collagen accumulation in a xenograft mouse model Fish oil as anti-inflammatory dietary intervention could prevent fibrogenesis in endometriosis
Hirakawa et al., 2019; B-catenin signaling inhibitors ICG-001 and C-82 improve fibrosis in preclinical models of endometriosis (Hirakawa et al., 2019)

  • N = 87 (4 * 10, donors); mice.

  • Intraperitoneal injection of donor uterine tissue

 ICG-001, 0, 10, 50, or 100 mg/kg IP thrice weekly Lesion size, Masson stain, Sirius red stain, IHC Number and weight of lesions, the extent of fibrosis, and α-SMA expression were reduced dose-dependently in treatment groups CBP/β-catenin signaling pathway is involved in endometriosis. Inhibition with ICG-001 and C-82 inhibits cell proliferation and promotes apoptosis. ICG-001 reduced lesion size and fibrosis in endometriosis mouse model B-catenin signaling inhibition by ICG-001 is a potential anti-fibrotic intervention in endometriosis
Hirakawa et al., 2022; Trophic and immunomodulatory effects of adipose tissue derived stem cells in a preclinical murine model of endometriosis (Hirakawa et al., 2022) N = 75 (5 * 10, 25); mice. Intraperitoneal injection of donor uterine tissue Adipose tissue-derived stem cells (ASCs), early (with stemness potential) and late (without) passage; early or late administration Lesion size, HE, Masson stain, IHC, RT-qPCR Day 1 and Day 15 administration of early ASCs (EASCs) reduced lesion size and fibrosis thickness, with no differences between control and late ASCs administration. EASCs reduced pro-inflammatory and pro-fibrotic cytokine expression, among which TGF-β1 Trophic and immunomodulatory properties of ASCs regulate pro-inflammatory and pro-fibrotic cytokines. Regenerative medicine could be an innovative treatment for endometriosis Early passage ASCs inhibited lesion development and fibrosis via inhibition of TGF-β1 and other pro-fibrotic cytokine expression, regardless of timing before or after lesion establishment
Hoorsan et al., 2022; The effectiveness of antioxidant therapy (vitamin C) in an experimentally induced mouse model of ovarian endometriosis (Hoorsan et al., 2022)

  • N = 14 (2 * 7); mice.

  • Autologous uterine tissue transplantation

 Vitamin C 50 mg/kg every 2 days orally Lesion size, HE, Masson Lesion size, adhesion score and fibrosis score reduced in treatment group. Follicle number increased in treatment group Vitamin C treatment reduced endometriosis development and increased fertility parameters of the ovaries Vitamin C reduced lesion size and fibrosis and increased fertility parameters
Huang et al., 2022a; Changing prostaglandin E2 (PGE2) signaling during lesional progression and exacerbation of endometriosis by inhibition of PGE2 receptor EP2 and EP4 (Huang et al., 2022a)

  • N = 168 (E1 90: 3 *20 + donors), E2 48: 4* 8 +donors

  • E3 30: 2 * 10 +donors); mice. Intraperitoneal injection of donor uterine tissue

  • PF-04418948 an EP2 inhibitor (EP2I) and ONOAE3- 208 an EP4 inhibitor (EP4I); metformin 200 mg/kg/day

  • Substance P for DE lesions model

 Lesion size, HE, Masson, IHC, hotplate latency Fibrosis increased over time, especially in DE. PGE2 signaling markers COX2, EP2 and EP4 increased in first 2 weeks and decreased later in development, correlated negatively with fibrosis. Hotplate latency of high dose EP2I and EP4I increased, in all EPI treatment groups markers of PGE2 signaling decreased and fibrosis increased. Metformin treatment decreased lesion size and extent of fibrosis and improved hotplate latency COX-2, EP2 and EP4 expression diminished over time with lesion development. EP2/EP4 inhibitors exacerbated hyperalgesia and increased fibrosis development, metformin reduced fibrosis and hyperalgesia Prostaglandin signaling diminished as fibrosis progressed, metformin reduced fibrosis development
Huang et al., 2022b; Tetramethylpyrazine retards the progression and fibrogenesis of endometriosis (Huang et al., 2022b)

  • N = 30 (3 *6 , 12 donors); mice.

  • Intraperitoneal injection of donor uterine tissue

 Tetramethylpyrazine (TMP) low (25 mg/kg) or high (100 mg/kg) dose Lesion size, HE, Masson, IHC, hotplate latency TMP treatment, in a dose-dependent manner, reduced lesion size, hyperalgesia, extent of fibrosis and lesional platelet aggregation, TGF-β, α-SMA and Col1 IHC expression. Extent of fibrosis correlated positively with lesion size and platelet aggregation and negatively with hotplate latency time TMP can reduce endometriotic lesion development via platelet aggregation inhibition and inhibition of EMT and FMT TMP can reduce fibrosis in endometriosis via platelet aggregation inhibition, underlining the importance of platelets in fibrogenesis
Hull et al., 2012; Host-derived TGF-β1 deficiency suppresses lesion development in a mouse model of endometriosis (Hull et al., 2012)

  • N = 27 (8, 19); mice.

  • Intraperitoneal injection of human endometrium

 TGF-β1−/− knockout Lesion size, HE, IHC Lesion weight, macrophage infiltration, α-SMA expression reduced in TGF-β−/− recipient mice Development of endometriosis depends on the availability of TGF-β1 in the peritoneal environment. Targeting the TGF-β1 pathway could suppress lesion development TGF-β1 has an essential role in fibrogenesis in endometriosis
Hull et al., 2005; Nimesulide, a COX-2 inhibitor, does not reduce lesion size or number in a nude mouse model of endometriosis (Hull et al., 2005)

  • N = 30 (2 * 8, 2 * 7); mice.

  • Intraperitoneal injection of human endometrium

 Nimesulide 25 mg/kg/day SC injection Lesion size, HE, IHC Lesion size, lesion number, α-SMA expression, macrophage infiltration, and vWF detected neovascularization did not differ between nimesulide treatment group and control Nimesulide did not inhibit endometriotic lesion formation in a mouse model. This suggests that COX-2 inhibition is unlikely to influence the establishment or progression of endometriosis COX-2 inhibition by nimesulide is not effective to reduce endometriosis and the associated myofibroblasts
Khan et al., 2018; Epigenetic therapy: novel translational implications for the arrest of environmental dioxin-induced disease in females (Khan et al., 2018)

  • N = 40 (4 * 10); mice.

  • Autologous uterine tissue transplantation

 TCDD (dioxin—toxic environmental contaminant activating CYP enzymes), garcinol (HATI—histone acetyltransferase inhibitor) Lesion size, HE, Masson stain, IHC, RT-qPCR TCDD exposure increased lesion size, the extent of fibrosis, and collagen expression. In additional HATI treatment group this effect was attenuated TCDD exposure increased disease progression and fibrosis via CYP3A4 activation. HATI treatment by garcinol activated KLF11 transcription factor, which diminished the disease progression by TCDD TCDD, an environmental contaminant is a pro-disease and pro-fibrotic stimulus. This effect can be attenuated by KLF11 activation via HATI treatment
Kim et al., 2017; Ginsenoside Rg3 decreased fibrotic and invasive nature of endometriosis by modulating miRNA-27b: in vitro and in vivo studies (Kim et al., 2017)

  • N = 60 (3 * 10, donors); mice.

  • Donor uterine tissue transplantation

 Rg3E high dose 0.2 mg/g/day, low dose 0.1 mg/g/day Lesion size, Masson stain, RT-qPCR Treatment groups showed smaller lesions and lower expression of MMP’s, CTGF, collagen, fibronectin and TGF-β1. Extent of fibrosis decreased dose dependently in treatment groups miRNA-27b-3p is elevated in endometriosis patients. Rg3E (Korean Red Ginseng extract) alters endometriosis characteristics by reducing miRNA-27b-3p and thereby inhibit invasion and fibrotic characteristics of endometriosis RgE3 can reduce miRNA-27b-3p and thereby reduce fibrosis
Li et al., 2016; Endometriotic mesenchymal stem cells significantly promote fibrogenesis in ovarian endometrioma through the Wnt/B-catenin pathway by paracrine production of TGF-β and Wnt1 (Li et al., 2016)

  • N = 54 (4 * 6, 5 * 6); mice.

  • Subcutaneous injection of human endometrium

 Intralesional injection of TGF- β1, Wnt1, TGF-β1+Wnt1, Ecto-MSC conditioned medium Lesion size, HE, Masson stain, IHC Fibrotic markers increased rapidly from day 14 after endometriosis establishment. Lesion size, extent of fibrosis, and collagen expression were equally increased in all treatment groups Ecto-MSC conditioned medium promoted proliferation, migration, invasion, and contraction of ecto-ESCs, as characteristics of fibrogenesis. Autocrine production of Wnt1 and TGF-β1 activated Wnt/B-catenin signaling, which stimulates fibrogenesis Mesenchymal stem cells promoted lesional progression and fibrosis, probably via Wnt1 and TGF-β1 signaling produced by them
Liu et al., 2015; Vascular endothelial growth factor receptor-2 inhibitor cediranib causes regression of endometriotic lesions in a rat model (Liu et al., 2015)

  • N = 20 (2 * 10); rat.

  • Autologous uterine tissue transplantation

 Cediranib 4 mg/kg/day Lesion size, HE, Masson stain, IHC, TUNEL apoptosis assay Lesion size, microvessel density, and proliferation decreased in the treatment group. The treatment group showed more fibrosis, but equal severe adhesions Cediranib caused regression of endometriotic implants, associated with decreased angiogenesis. Fibrosis increased, but without severe adhesions Fibrosis increased by treatment with an angiogenesis inhibitor
Liu et al., 2019; Sensory nerve-derived neuropeptides accelerate the development and fibrogenesis of endometriosis (Liu et al., 2019)

  • N = 124 (E1: 3 * 7, donors; E2: 3 * 8; E3: 4 * 8, donors); mice.

  • E1, E3: Intraperitoneal injection of donor uterine tissue

  • E2: Subcutaneous injection of human endometrium

  • E1: chemical sympathetic denervation by 6-hydroxydopamine (OHDA), sensory denervation by resinaferatoxin (RTX).

  • E2: surgical denervation.

  • E3: substance P, aprepitant

 Lesion size, HE, Masson stain, IHC, hotplate latency E1: Lesion size, fibrotic markers, proliferation, angiogenesis, and neurokinin receptor 1 (NK1R) expression decreased in chemical denervation groups, most extensively effect by sensory denervation with RTX Sensory nerves or the NK1R signaling pathway are important in the development of fibrogenesis in endometriosis and may be potential targets for intervention (Sensory) nerves and the NK1R signaling pathway stimulate fibrogenesis in endometriosis
E2: Lesion size, fibrotic markers and NK1R expression decreased, hotplate latency improved in surgical denervation groups, both before and after endometriosis induction
E3: Lesion size, fibrotic markers, EMT, FMT, and SMM markers increased, and hotplate latency impaired in the substance P treatment group, but markers decreased and hotplate latency improved in NK1R antagonist (aprepitant) group
Luo et al., 2020; Sodium tanshinone IIA sulfonate restrains fibrogenesis through induction of senescence in mice with induced deep endometriosis (Luo et al., 2020)

  • N = 72 (6 * 8, donors); mice.

  • Intraperitoneal injection of donor uterine tissue

 Sodium tanshinone IIA (STS) high or low dose Lesion size, HE, Masson stain, IHC Lesion size, the extent of fibrosis, and macrophage (M2) infiltration were reduced, cell senescence markers and apoptosis were increased and hotplate latency improved in the STS treatment group, most extensively in high dose STS treatment reduced lesion weight and extent of fibrosis in the deep endometriosis model, seemingly through induction of cellular senescence and increased apoptosis and reduced lesional infiltration of M2 macrophages Sodium tanshinone reduced fibrosis through cellular senescence and apoptosis induction
Marcellin et al., 2017; Alteration of Nrf2 and glutamate cysteine ligase expression contribute to lesions growth and fibrogenesis in ectopic endometriosis (Marcellin et al., 2017)

  • N = 75 (E1: 16, 14, donors; E2: 2 * 10, donors); mice.

  • Donor uterine tissue transplantation

  • E1: NRF2−/− knockout donor mice or wild-type donor control.

  • E2: dimethyl-fumarate (DMF)

 Lesion size, HE, Sirius red stain, RT-qPCR Knockout implants were larger and larger extent of fibrosis. Lower lesion weight and smaller extent of fibrosis in DMF treatment group Decreased Nrf2 expression is associated with decreased GCL expression and are both present in endometriosis in women. Via oxidative stress this can lead to an increased fibrogenesis as shown in an in vivo experiment by Nrf2 knockout and DMF treatment Decreased Nrf2 expression can contribute to fibrosis in endometriosis and could be a potential therapeutic target
Matsuzaki et al., 2013; Involvement of the Wnt/B-catenin signaling pathway in the cellular and molecular mechanisms of fibrosis in endometriosis (Matsuzaki and Darcha, 2013)

  • N = 80 (4 * 10, 4 * 10); mice.

  • Subcutaneous injection of human endometrium

 CGP049090, Tcf/β-catenin antagonist, 2 mg/kg/day Lesion size, Masson stain, Sirius red stain Fibrosis develops between day 7 and day 14 after model establishment. Smaller extent of fibrosis in CGP049090 treatment groups, both in early treatment start and late treatment start groups Wnt/β-catenin targeting inhibits fibrogenesis in vitro and in vivo in mouse models, in vivo experiments showed the possibility to reverse established fibrosis Wnt/β-catenin signaling pathway effective target to prevent and reverse fibrosis
Matsuzaki et al., 2014; Antifibrotic properties of epigallocatechin-3-gallate in endometriosis (Matsuzaki and Darcha, 2014)

  • N = 40 (4 * 10); mice.

  • Subcutaneous injection of human endometrium

 EGCG (epigallocatechin-3-gallate, intraperitoneal injection 50 mg/kg/day) Lesion size, Masson stain, Sirius red stain In treatment group started before fibrosis development extent of fibrosis was comparable with fibrosis directly after lesion establishment. In treatment group started after fibrosis development extent of fibrosis was smaller compared with controls but larger compared with fibrosis directly after lesion establishment ECGC treatment inhibited TGF-β1-stimulated activation of MAPK and Smad signaling pathways thereby preventing endometriosis development and fibrogenesis in vivo ECGC treatment inhibited fibrogenesis via MAPK and Smad signaling but did not reverse already established fibrosis
Miller et al., 2021; Interleukin-33 activates group 2 innate lymphoid cell expansion and modulates endometriosis (Miller et al., 2021)

  • N = 25 (5 * 5, donors); mice.

  • Donor uterine tissue transplantation

 IL-33 suppletion, ILC2 antibody depletion by CD90.2 or IL-33 antibody neutralization, wild type or RAG2−/− knockout or RAG2−/− IL2ry−/− knockout mice HE, Masson stain, IHC IL-33 treated wild-type mice showed increased extent of fibrosis. IL-33 treated RAG2−/− mice showed increased extent of fibrosis. Both RAG−/− aCD90.2 and RAG2−/− IL-2ry−/− showed no increased extent of fibrosis after IL-33 treatment. IL-33 neutralizing AB treatment decreased extent of fibrosis IL-33 has an essential role in endometriosis development through ILC2s (group 2 innate lymphoid cells) via stimulating inflammation, immune cell recruitment, lesion proliferation and fibrosis IL-33 acts via innate lymphoid cells to stimulate endometriosis, various therapeutic strategies inhibiting this pathway inhibited fibrogenesis
Mishra et al., 2020; Mouse model for endometriosis is characterized by proliferation and inflammation but not epithelial-to-mesenchymal transition and fibrosis (Mishra et al., 2020)

  • N = 20; mice.

  • Autologous uterine tissue transplantation

 None HE, Masson stain, Picrosirius red stain, IHC, RT-qPCR Adhesion were progressively present. Some collagen IV was detected, collagen I was only detected in muscle layers, not in lesions. No collagen or α-SMA was detected within stromal area Implantation of autologous uterine fragments leads to the development of ectopic endometrial lesions. The lesions grew progressively and showed inflammatory activity. The lesions did not show EMT or fibrosis No fibrosis or myofibroblastic differentiation was detected in the used mouse model of endometriosis
Mohankumar et al., 2020; Bis-indole-derived nuclear receptor 4A1 (NR4A1, Nur77) ligands as inhibitors of endometriosis (Mohankumar et al., 2020)

  • N = 16 (2 * 5, 2 * 3); mice.

  • Intraperitoneal injection of donor uterine tissue;

  • Intraperitoneal injected human endometriotic cell line

 C-DIM (methylene substituted diindolylmethane, a NR4A1 antagonist) Lesion size, HE, IHC, luciferase activity Lesion size and α-SMA expression were reduced whereas apoptosis markers increased in treatment group in the mouse donor tissue experiment. In the human donor model lesion size was reduced and apoptosis markers were increased in the treatment group, fibrosis was not assessed in this model NR4A1 is a pro-endometriotic transcription factor and inhibition with Bis-indole-derived antagonist is promising as a new nonhormonal therapy: it reduced growth and α-SMA expression of implants NR4A1 antagonist therapy is a potential anti-fibrotic target
Muraoka et al., 2023; Fusobacterium infection facilitates the development of endometriosis through the phenotypic transition of endometrial fibroblasts (Muraoka et al., 2023)

  • N = 149 (60, 36, 27, 26); mice.

  • Intraperitoneal injection of donor uterine tissue

  • Fusobacterium nucleatum, Lactobacillus iners or Escherichia coli infection in endometrium of donor mice.

  • Antibiotic treatment of donor or recipient mice by metronidazole (MZ) and chloramphenicol (CP)

 Lesion size, IHC, IF F. nucleatum also present in endometriosis from infected donors, this group showed larger implants, increased M2 macrophage infiltration, TGF-β and TAGLN expression, not the case for L. iners or E. coli infected donor implants. TAGLN siRNA in recipients reduced stimulating effect of F. nucleatum infection. Antibiotic treatment in donor or recipient mice reduced lesion development as well F. nucleatum endometrial infection can trigger TAGLN expression via TGF-β signaling, resulting in a fibroblastic phenotype more prone to lead to endometriotic lesion implantation and development. This effect can be reversed by antibiotic elimination of F. nucleatum F. nucleatum can trigger fibroblast to myofibroblast transdifferentiation marked by TAGLN, resulting in an increased endometriotic implantation rate. This effect can be reversed by antibiotic based elimination of F. nucleatum
Nagai et al., 2020; Focal adhesion kinase-mediated sequences, including cell adhesion, inflammatory response, and fibrosis, as a therapeutic target in endometriosis (Nagai et al., 2020)

  • N = 25 (13, 12, donors); mice.

  • Intraperitoneal injection of donor uterine tissue

 FAK inhibitor PF573228 Lesion size, HE, IHC Lesion size, proliferation score, MCP-1, TGF-β1, and α-SMA expression were decreased in FAK inhibition treatment group. Non-treatment group showed thicker, more fibrotic cyst walls FAK-inhibition reduced lesion development, TGF-B1 expression, myofibroblastic changes, and macrophage infiltration and thus could be a promising anti-endometriotic treatment pathway FAK signaling promotes fibrogenesis
Nahari and Razi, 2018; Silymarin amplifies apoptosis in ectopic endometrial tissue in rats with endometriosis; implication on growth factor GDNF, ERK1/2, and Bcl-6b expression (Nahari and Razi, 2018)

  • N = 12 (2 * 6, donors); rat.

  • Autologous uterine tissue transplantation

 Silymarin (flavonoid mixture) 50 mg/kg/day Lesion size, HE, Masson stain, IHC Lesion size and the number of apoptotic cells were increased and BCL-6b and BCL-2 expression decreased in the treatment group, whereas the extent of fibrosis was increased in the treatment group SMN acts as an anti-inflammatory and anti-oxidant agent and inhibits endometriosis growth by diminishing GDNF, reducing Bcl-2/6b, but enhances ERk1/2 expression and fibrosis Silymarin reduced lesion size via inducing apoptosis, but increased fibrosis via Erk signaling
Nishimoto-Kakiuchi et al., 2016; Characteristics of histologically confirmed endometriosis in cynomolgus monkeys (Nishimoto-Kakiuchi et al., 2016)

  • N = 8; Cynomolgus monkey.

  • Spontaneous endometriosis

 None HE, IHC, Iron staining CD10 staining present in lesions. Hemorrhage and inflammation often observed, hemosiderin-laden macrophages and iron deposits present. Α-SMA staining in all cases, surrounding lesions. Nerve fibers present in most cases Spontaneous endometriosis in Cynomolgus monkeys exhibits characteristics similar to human disease Myofibroblast differentiation is a characteristic of endometriosis in Cynomolgus monkeys
Nishimoto-Kakiuchi et al., 2023; A long acting anti IL-8 antibody improves inflammation and fibrosis in endometriosis (Nishimoto-Kakiuchi et al., 2023)

  • N = 24 (4 spontaneous, 20 models); Cynomolgus monkey.

  • Autologous endometrial tissue transplantation and intraperitoneal injection

 AMY109 (long-acting anti IL-8 antibody) Laparoscopy at 3, 6, 9, and 12 months for ASRM and lesion size, HE, Sirius red, IHC Anti-IL-8 antibody treatment reduced ASRM score, fibrosis, and α-SMA expression in 2 of 4 with spontaneous endometriosis. AMY109 treatment stabilized ASRM size (versus increase in no treatment group), reduced lesion size and fibrosis in the model monkeys AMY109 anti-IL-8 antibody stopped lesional progression and reduced fibrosis in endometriosis in cynomolgus monkeys, being a potential endometriosis drug Anti-IL-8 therapy has potential as anti-fibrotic therapy in endometriosis
Odagiri et al., 2009; Smooth muscle metaplasia and innervation of interstitium of endometriotic lesions related to pain (Odagiri et al., 2009)

  • N = 10 (2 * 5); rat.

  • Autologous uterine tissue transplantation

 None HE, IHC Fibrotic interstitium and intensely α-SMA stained areas present in ectopic lesions, around the formed cysts. NCAM and NGF staining present in ectopic lesions, not in healthy endometrium Presence of smooth muscle metaplasia and nerve fibers suggests a role of smooth muscle contraction in the endometriosis-associated pain Histo-anatomical relationship between myofibroblasts and highly innervated interstitium suggests a role in pain
Peng et al., 2022; Mechanisms of Thunberg Fritillaria in treating endometriosis based on network pharmacology and the effect of Peiminine on the MEK/ERK pathway (Peng et al., 2022)

  • N = 60 (6 * 10); mice.

  • Autologous uterine tissue transplantation

 Peiminine low dose 2 mg/kg/day, medium dose 4 mg/kg/day, high dose 8 mg/kg/day, dienogest 2 mg/day HE, Masson stain, IHC, immunofluorescence, WB, RT-qPCR Extent of fibrosis and expression of vimentin as EMT marker were decreased in treatment groups. Markers for MAPK/ERK signaling were decreased in peiminine groups Peiminine, as an active component in Thunberg Fritillaria, can downregulate the MAPK/ERK signaling pathway to suppress endometriosis Peiminine showed anti-fibrotic potential in endometriosis via MAPK/ERK signaling pathway
Riccio et al., 2019; B lymphocytes inactivation by ibrutinib limits endometriosis progression in mice (Riccio et al., 2019)

  • N = 30 (3 * 10, donors); mice.

  • Donor uterine tissue transplantation

 Ibrutinib or anti-CD20 Lesion size, HE, Sirius red stain, ELISA, RT-qPCR, ultrasonography Lesion size and expression of COX-2, α-SMA and collagen were decreased in Ibrutinib treatment group, not affected in anti-CD20 treatment group. M1/M2 ratio decreased in spleen, increased in peritoneal cavity after ibrutinib treatment Bruton’s tyrosine kinase inhibition by Ibrutinib decreased endometriosis progression in mice, by shifting activated B cells to Bregs, while B cell depletion by CD20 antibody treatment had no effect. Peritoneal increase of M1/M2 ratio is a new perspective in treating endometriosis Endometriosis lesion size and fibrotic markers decreased after Bruton’s tyrosine kinase inhibition, probably because of a decreased B cell activity
Shi et al., 2021; WEE1 promotes endometriosis via the Wnt/β-catenin signaling pathway (Shi et al., 2021)

  • N = 40 (4 * 10); mice.

  • Intraperitoneal injection of autologous uterine tissue

 WEE1 inhibitor (AZD1775) with or without estrogen suppletion HE, Masson stain, RT-qPCR WEE1 is upregulated by IL-1β. WEE1 upregulation inhibited apoptosis, WEE1 knockdown promoted apoptosis, and attenuated fibrosis. Fibrotic markers were decreased in WEE1 inhibition treatment group. WEE1 and fibrotic marker expression increased in estrogen suppletion group. WEE1 stimulated ectopic stromal cell migration and fibrosis, via Wnt/β-catenin pathway WEE1 promotes fibrogenesis via the Wnt/β-catenin pathway. Wnt/β-catenin inhibitor inhibits fibrogenesis
Shi et al., 2020; Mechanistic study of vitamin C attenuation of endometriotic fibrosis (Shi et al., 2020)

  • N = 17 (2 * 7, 3); rats.

  • Autologous uterine tissue transplantation

 Vitamin C 500 mg/kg/day IP Lesion size, HE, Masson stain, RT-qPCR Lesion size, extent of fibrosis, and expression of collagen I, α-SMA, TGF-β1 and CTGF were decreased in the vitamin C treatment group Vitamin C treatment decreased endometriosis lesion size and fibrotic marker protein and mRNA expression in a rat model Vitamin C can reduce fibrosis in endometriosis
Siracusa et al., 2021; The methyl ester of 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid reduces endometrial lesions development by modulating the NF-κB and Nrf2 pathways (Siracusa et al., 2021)

  • N = 18 (3 * 3, donors); rats.

  • Intraperitoneal injection of donor uterine tissue

 CDDO-Me 5 mg/kg/day IP Lesion size, He, Masson stain, IHC, WB, anti-oxidant activity assay Lesion size, extent of fibrosis, α-SMA, fibronectin and BCL expression and NF-κB activation were decreased in treatment group The methyl ester of 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid (CDDO-Me) reduces endometriotic lesion development by modulating the NF-κB and Nrf2 pathways CDDO-Me can reduce fibrosis via NF-κB and Nrf2 pathways
Taskin et al., 2016; A humanized anti-interleukin (IL)-6 receptor monoclonal antibody, tocilizumab, for the treatment of endometriosis in a rat model (Taskin et al., 2016)

  • N = 30 (13, 9, model failed in the rest); rats.

  • Autologous uterine tissue transplantation

 Tocilizumab 8 mg/kg/2 weeks IP HE, Masson stain, IHC Lesion size reduced over time in tocilizumab treatment group, but stable in controls. IL-6 expression was comparable between groups. Extent of fibrosis and expression of VEGF was decreased in the treatment group Tocilizumab (IL-6 receptor mAB) had a regressive effect on endometriosis implants in a rat model IL-6 inhibition by tocilizumab decreased lesion size and fibrosis
Umezawa et al., 2012; Expression profile of extracellular matrix and adhesion molecules in the development of endometriosis in a mouse model (Umezawa et al., 2012)

  • N = 20 (12, 8); mice.

  • Autologous uterine tissue transplantation

 None HE, RT-qPCR Expression of collagens (3a1, 8a1, 1a1), Tnc, Vtn, Lamc1,2 were increased 7 days post-induction vs. sham-operated mice. Lamc2 peaked at 24 h, all other mRNAs at day 7 RNA expression of integrins, collagens, other ECM proteins peaked at 7 days post-induction. Lamc2 peaked within 24 h, suggesting a role in the initiation of endometriosis Lamc2 expression could have a role in the initiation of fibrotic development of endometriosis
van Kaam et al., 2008; Fibromuscular differentiation in deeply infiltrating endometriosis is a reaction of resident fibroblasts to the presence of ectopic endometrium (van Kaam et al., 2008)

  • N = 8; mice.

  • Intraperitoneal and subcutaneous injection of human endometrial tissue

 None HE, IHC α-SMA highly present 1 week after induction in mouse cells surrounding lesion, not in human stromal cells. Two weeks after induction α-SMA slightly decreased in mouse cells and decline progressively to week 3 and 4. Collagen deposition increased over time α-SMA expression is induced in the host tissue, suggesting a local reaction to ectopic endometrium leading to FMT rather than FMT of the ectopic cells itself Myofibroblast differentiation is a reaction of resident fibroblasts rather than endometrial fibroblasts in a mouse model
Wang et al., 2023; PIM2 promotes the development of endometriosis by enhancing glycolysis and fibrosis (Wang et al., 2023)

  • N = 30 (5, 5, 10, donors); mice.

  • Intraperitoneal injection of donor uterine tissue

 PIM2 knockout donor and/or recipient mice; SMI4a (PIM2 inhibitor) Lesion size, HE, IHC Lesions from PIM2 d/d in WT and PIM2 d/d in PIM2 d/d recipients were smaller than WT to WT lesions, SMI4a treatment in WT to WT decreased lesion size. In knockout and treatment groups expression of α-SMA and markers of EMT and FMT was decreased PIM2 upregulation in endometriosis promotes glycolysis and fibrosis in ectopic lesions, and may be a potential therapeutic target PIM2 promotes EMT, FMT, and fibrosis in endometriosis, via upregulation of glycolysis
Wu et al., 2018; Exosomal miR-214 from endometrial stromal cells inhibits endometriosis fibrosis (Wu et al., 2018)

  • N = 12 (3 * 4); mice.

  • Intraperitoneal injection of human endometrium

 miRNA-214 loaded exosomes HE, Masson stain, Sirius red stain, IHC, RT-qPCR Extent of fibrosis on Masson and Sirius red stain and expression of CTGF and collagen A1 protein and mRNA expression was reduced in exosomal miRNA treatment group Fibrosis was associated with elevated fibrotic markers CTGF, collagen A1, and α-SMA and a diminished miR-214 expression. miR-214 impacts fibrogenesis via CTGF pathway. miR-214 treatment decreased fibrogenesis in mice and is possible via exosome treatment miRNA-214 therapy is anti-fibrotic and administration is possible via exosomes
Xia et al., 2023; Neferine mediated TGF-β/ERK signaling to inhibit fibrosis in endometriosis (Xia et al., 2023)

  • N = 60 +donors (6 * 10); mice.

  • Intraperitoneal injection of donor uterine tissue

 Neferine low dose (5 mg/kg/day), medium dose (10 mg/kg/day), high dose (30 mg/kg/day), dienogest (2 mg/day) Lesion size, HE, Masson stain, IHC, IF, WB Fibrosis was progressive from day 7 to day 21. Fibrosis decreased in all treatment groups. Fibrotic markers α-SMA, Col-1, CTGF, FN, TGF-β, and p-ERK were increased in all study groups compared to healthy mice but decreased in all treatment groups versus untreated model mice. Largest effect of neferine was observed in high dose group Inhibition of TGF-β/ERK signaling pathway by neferine can inhibit fibrosis progression in endometriosis TGF-β/ERK signaling pathway contributes to fibrosis in endometriosis and this pro-fibrotic signaling can be inhibited by neferine
Xiao et al., 2020; Platelet and regulatory T cells may induce a type 2 immunity that is conducive to the progression and fibrogenesis of endometriosis (Xiao et al., 2020)

  • N = 120 (2 * 24, 4*8, donors); mice.

  • Intraperitoneal injection of donor uterine tissue

 Anti-platelet antibody therapy; regulatory T cell depletion; joint depletion platelets and Tregs Lesion size, Masson stain, IHC, hotplate latency Lesion size and extent of fibrosis increased over time in control group. Lesion weight was reduced in intervention group only after 5 weeks. Lesion size, markers for EMT, FMT and extent of fibrosis were reduced in platelet, T regs and joint depletion groups, hotplate latency improved. Type 2 immune reaction cell aggregation, Smad and Akt signaling markers were decreased in intervention groups Platelets stimulate aggregation of Tregs, Th2 and M2 cells, which facilitated TSLP and GARP expression and TGF-β1 stimulation resulting in fibrogenesis and lesion progression. Platelet and Treg depletion reduced lesions progression by disrupting a type 2 immune reaction. Type 2 immune reaction plays a vital role in fibrogenesis in endometriosis Fibrogenesis is stimulated via aggregation of regulatory T cells and M2 cells by platelets
Xu et al., 2023; A novel pathway regulating pyroptosis-induced fibrosis in endometriosis via Inc-MALAT1/miR-141-3p/NLRP3 pathway (Xu et al., 2023) N = 24 (3 * 8); mice. Donor uterine tissue transplantation MCC950 50 mg/kg (NLRP3 inhibitor) HE, Masson stain, IHC, WB MCC950 deactivated NLRP3 and decreased pyroptosis markers and IL-1β. Extent of fibrosis, expression of TGF-β1, CTGF, α-SMA, collagen-I and FN-1 were reduced by MCC950 treatment Lnc-MALAT1 inhibits the inhibitory effect of miR-214-3p on NLRP3 inflammasome, thereby increasing pro-fibrotic signaling Increased lnc-MALAT1 promotes fibrosis in endometriosis via its inhibiting role on the anti-fibrotic miR-214-3p, via increased NLRP3 inflammasome signaling
Yan et al., 2019a; The establishment of a mouse model of deep endometriosis (Yan et al., 2019a)

  • N = 48 (4 * 8, 16 donors), mice.

  • Intraperitoneal injection of donor uterine tissue

 Substance P (SP), calcitonin gene-related peptide (CGRP), SP+CGRP Lesion size, Masson stain, IHC, hotplate latency Lesion size, adhesion scores, extent of fibrosis, α-SMA, and other EMT, FTM, SMM marker expression was increased in treatment groups, especially in combined treatment. FMT progressive over time. Hotplate latency was impaired in treatment groups and showed a positive correlation with EMT, FMT, SMM markers, fibrosis and lesion weight. Correlation stronger with fibrosis than with lesion size The developed DE model is macroscopically and microscopically similar to human lesions. There is a close correlation between fibrosis and EMT, FMT, and SMM. SP, and CGRP accelerate lesion development through EMT, FMT, and SMM Substance P and CGRP stimulate endometriotic lesion development and fibrogenesis. Fibrosis important determinant of pain behavior
Yin et al., 2020; Enriched environment decelerates the development of endometriosis in mice (Yin et al., 2020)

  • N = 95 (4 * 10, 2 * 10, 35 donors); mice.

  • Intraperitoneal injection of donor uterine tissue

 Enriched environment (EE): larger cages, more social interactions, toys, and physical activity. Either EE before and after induction of in-donors Lesion size, Masson stain, IHC, hotplate latency Lesion size, the extent of fibrosis, and α-SMA expression were reduced and hotplate latency improved in the enriched environment before and after lesion establishment group. No significant effects of enriched environment after lesion establishment or for donors. Plasma leptin levels showed a positive correlation with fibrosis and a negative with PPAR-γ expression Enriched environment decelerates endometriosis development, attenuates hyperalgesia, and reduced fibrogenesis. Likely through increased dopamine receptor D2 and decreased adrenergic receptor B2 Positive environmental factors can prevent endometriosis development, with no effect after lesion development
Yin et al., 2018; Caloric restriction dramatically stalls lesion growth in mice with induced endometriosis (Yin et al., 2018)

  • N = 60 (2 * 10, 2 * 10, 20 donors); mice.

  • Intraperitoneal injection of donor uterine tissue

 Caloric restriction (CR), 30% reduction compared to ad libitum group Lesion size, Masson stain, IHC, hotplate latency Lesion size, extent of fibrosis, angiogenesis, proliferation and expression of IGF1, mTOR and pAkt were reduced in caloric restriction before and after lesion induction groups. No differences in hotplate latency were observed Caloric restriction reduced lesion weight and fibrogenesis, both if started before or after induction of lesions. IHC suggests involvement of PI3K/Akt/mTOR, AMPK, SIRT1, CREB signaling pathways via reduced angiogenesis, proliferation and estrogen production Caloric restriction may decrease fibrosis in endometriosis
Yoshino et al., 2020; Relaxin-2 may suppress endometriosis by reducing fibrosis, scar formation, and inflammation (Yoshino et al., 2020)

  • N = 16 (6, 10); mice.

  • Donor uterine tissue transplantation

 Relaxin-2 1 μg/g/day Lesion size, Masson stain Lesion size and extent of fibrosis were decreased in RLX-2 treatment group Relaxin-2 treatment inhibits fibrogenesis and inflammation in endometriosis both in vitro and in a mouse model. Possibly via MAPK pathway Relaxin-2 effective anti-fibrotic therapy in a mouse model
Zeng et al., 2018; NR4A1 is involved in fibrogenesis in ovarian endometriosis (Zeng et al., 2018)

  • N = 80 (2 * 10, 30, 2 * 15); mice.

  • Autologous uterine tissue transplantation

  • Intraperitoneal injection of human endometrium

 E1: NR4A1−/− knockout; E2: Cytosporone (Csn-B) (NR4A1 agonist) Lesion size, HE, Masson stain, Sirius red stain, WB, IHC, RT-qPCR NR4A1 expression decreased and fibrosis increased in NR4A1−/− mice. Csn-B treatment did not affect lesion size. NR4A1 expression increased, p-NR4A1 and extent of fibrosis decreased in Csn-B treatment group TGF-β1 stimulation phosphorylated NR4A1 through AKT pathway. NR4A1 deficiency promoted fibrosis and Csn-B treatment (a NR4A1 agonist) inhibited this effect and decreased fibrosis in vitro and in a mouse model NR4A1 has anti-fibrotic properties, phosphorylated NR4A1 has pro-fibrotic properties, both acting via AKT and TGF- β1 signaling
Zhang et al., 2016b; Cellular changes consistent with epithelial-mesenchymal transition and fibroblast-to-myofibroblast transdifferentiation in the progression of experimental endometriosis in baboons (Zhang et al., 2016b)

  • N = 22; baboons.

  • Autologous menstrual endometrium intraperitoneal inoculation

 None Lesion size, adhesion score, HE, Masson stain, IHC, IF TGF-β, p-Smad3 and CD42 were progressive over time. Vimentin expression in epithelial cells was absent till 12 months. Different α-SMA expression pattern was observed between intrastromal and surrounding cells, both increased over time. E-cadherin decreased over time. E-cadherin correlated negatively, α-SMA positively with TGF-βand p-Smad3. Fibrosis, desmin and smooth-muscle myosin heavy chain increased progressively from 3 months onward Repeated tissue injury and repair occurs in endometriotic lesions, leading to EMT, FMT and SMM and ultimately fibrosis Progressive EMT and FMT are on the basis of over time progressive smooth muscle metaplasia and fibrosis
Zhang et al., 2017a; Enhancer of Zeste homolog 2 (EZH2) induces epithelial mesenchymal transition in endometriosis (Zhang et al., 2017a)

  • N = 50 (3 * 8, 2 * 7, donors); mice.

  • Intraperitoneal injection of donor uterine tissue

 3-deazane-planocin A (DZNep, a EZH2 inhibitor) 1 mg/kg or 2.5 mg/kg Lesion size, IHC, hotplate latency Lesion size was reduced dose-dependently in DZNep treatment groups. Expression of α-SMA, collagen 1A and markers for EMT were decreased and hotplate latency improved in DZNep treatment groups EZH2 and associated PRC2 are elevated in endometriosis. EZH2 inhibition suppresses PRC2 expression and EMT activating factors. In vivo EZH2 inhibition with DZNep improved hyperalgesia and reduced EMT and fibrosis in endometriosis mouse model. Platelets can activate EZH2 activity in endometriotic cells Enhancer of Zeste homolog 2 induces EMT leading to fibrosis, probably after activation by platelets
Zhang et al., 2017b; Progressive development of endometriosis and its hindrance by anti-platelet treatment in mice with induced endometriosis (Zhang et al., 2017b)

  • N = 90 (2 * 30, donors); mice.

  • Intraperitoneal injection of donor uterine tissue

 Tanshinone IIA 12.5 μg/g/2 days Lesion size, Masson stain, IHC Lesion size, extent of fibrosis and expression of markers for EMT, FMT and SMM are progressive over time. Hotplate latency impaired over time. In tanshinone IIA treatment group progression was not observed. Lesion development and fibrosis were decreased and hotplate latency improved in treatment group Endometriosis model in mouse undergo progressive EMT, FMT, SMM, and fibrosis over time. Tanshinone IIA, an anti-platelet drug, inhibits these processes and reduced lesion weight Anti-platelet therapy by tanshinone IIA is effective to stop endometriosis development and fibrogenesis
Zhang et al., 2019b; Activin A promotes myofibroblast differentiation of endometrial mesenchymal stem cells via STAT3-dependent Smad/CTGF pathway (Zhang et al., 2019b)

  • N = 42 (4 * 7, 14 donors); mice.

  • Intraperitoneal injection of donor uterine tissue

 Activin A, anti-Activin A antibody (AB) Masson stain, IHC Extent of fibrosis and expression of α-SMA, collagen I, fibronectin and CTGF were increased in Activin A treatment group versus non-treated control and decreased in the anti-Activin A AB treatment group Activin A promotes myofibroblast differentiation via STAT3-dependent Smad/CTGF pathway. Activin A inhibition suppresses fibrosis development in mice Activin A promotes myofibroblast differentiation and fibrosis via Smad signaling, inhibition can be a potential therapeutic target
Zhang et al., 2022; Ferroptosis induced by iron overload promotes fibrosis in ovarian endometriosis and is related to subpopulations of endometrial stromal cells (Zhang et al., 2022) N = 30 (6 * 5); mice. Subcutaneous injection of human endometrial tissue Control, ferric ammonium citrate (FAC), erastin, FAC + vehicle, FAC+DFO (deferoxamine mesylate, iron chelator), FAC + Fer1 (Ferrostatin-1, ferroptosis inhibitor) Lesion size, HE, IHC, malondialdehyde assay FAC treatment enlarged lesion size and enhanced fibrosis, this effect was diminished by Fer-1 and DFO treatment Mesenchymal stem cell ferroptosis can be induced by endometriosis iron overload, leading to increased fibrosis Iron accumulation in endometriosis can trigger ferroptosis and subsequentially fibrogenesis
Zhang et al., 2023a; Blocking sphingosine 1-phosphate receptor 1 with modulators reduces immune cells infiltration and alleviates endometriosis in mice (Zhang et al., 2023a)

  • N  = 68 (3 * 5, 6, 6 donors; 3 * 9, 14 donors); mice.

  • Donor uterine tissue transplantation

 Broad-spectrum S1P modulator FTY720; selective S1P receptor 1 modulator SEW2871 Lesion size, ultrasonography, HE, Masson stain, IHC, RT-qPCR, flow cytometry 1 mg/kg FTY720 was identified as adequate dosage. In both treatment groups lesion size and extent of fibrosis, but not α-SMA expression, was decreased. Inflammatory markers IL-1β, TGF-β1, and TNF-α only decreased in SEW2871 group. Immune cell lesional infiltration of CD45+ cells and macrophages, but not CD4+ or CD8+ T cells was decreased in both treatment groups Both broad and specific S1P receptor modulator decreased endometriosis development via a decreased immune cell infiltration S1P receptor modulators can reduce immune cell infiltration and fibrosis in endometriosis
Zheng et al., 2016; Epigenetic modulation of collagen 1A1: therapeutic implications in fibrosis and endometriosis (Zheng et al., 2016)

  • N = 78 (2 * 8, 6 * 10); mice.

  • Donor (E1) or autologous (E2) uterine tissue transplantation

  • E1: Klf11−/− donor lesions implanted to WT mice and vice versa.

  • E2: WT or Klf11−/− mice. Garcinol (histone acetyl transferase inhibitor), suberoyl anilide hydroxamic acide (SAHA, histone deacetylase inhibitor)

 Lesion size, Masson stain, RT-qPCR

  • E1: Lesion size, extent of fibrosis and COL1A1 expression increased in WT mice with Klf11−/− donor lesions compared to vice versa model.

  • E2: In Klf11−/− model treatment with garcinol decreased extent of fibrosis and expression of collagen. In WT model SAHA treatment increased collagen expression and extent of fibrosis

 Progressive fibrosis is associated with lesion specific diminished Klf11 expression. Klf11 resulted in histone deacetylation and gene repression of COL1a1. Epigenetic therapy can affect (de)acetylation and thereby is a potential therapeutic strategy Klf11 repress collagen production and thus fibrogenesis, loss of Klf11 has a pro-fibrotic effect. Epigenetic therapy can be a target for treatment
Zheng et al., 2023a; Aberrant expression of histone deacetylase 8 in endometriosis and its potential as a therapeutic target (Zheng et al., 2023a)

  • N = 24 (2 * 8, 8 donors); mice.

  • Intraperitoneal injection of donor uterine tissue

 PCI- 34051 (HDAC8 inhibitor) Lesion size, HE, Masson stain, IHC, hotplate latency Hdac 8 was overexpressed in endometriotic lesions. Hdac 8 inhibition reduced endometriotic lesion development and improved hyperalgesia Hdac 8 is correlated with lesion development and Hdac 8 inhibition treatment showed therapeutic potential Hdac 8 inhibition can reduce fibrosis in endometriosis
Zheng et al., 2023b; Corroborating evidence for aberrant expression of histone deacetylase 8 in endometriosis (Zheng et al., 2023b)

  • N = 124 (7 * 6, 18 donors; 2 * 8, 8 donors; 5 * 5, 15 donors); mice.

  • Intraperitoneal injection of donor uterine tissue

 TM-2-51 (HDAC8 activator); Tubastatin A (HDAC6 inhibitor), PCI- 34051 (HDAC8 inhibitor) Lesion size, HE, Masson stain, IHC, WB, hotplate latency Hdac 1, 8, and 6 expression was progressive over time, correlating with fibrosis, but Hdac 2 expression decreased over time. Hdac 8 staining correlated most prominent with lesional fibrosis. Lesional development and fibrosis was increased in Hdac8 activator group and decreased in Hdac inhibitors treatment groups Hdac 8 expression is progressive during endometriotic lesions development, correlating with fibrosis and Hdac based treatment can be a therapeutic target Hdac-based interventions showed anti-fibrotic properties in endometriosis

PER, peritoneal endometriosis; OMA, ovarian endometrioma; DE, deep endometriosis; WT, wild-type; HE, hematoxylin/eosin staining; IHC, immunohistochemistry; IF, immunofluorescence; WB, western blot; RT-qPCR, real-time qualitative polymerase chain reaction; α-SMA, α-smooth muscle actin; TGF-β, transforming growth factor-β; EMT, epithelial-to-mesenchymal transition; FMT, fibroblast-to-myofibroblast transdifferentiation; SMM, smooth muscle metaplasia.