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. 2024 Dec 28;76(3):264–270. doi: 10.3164/jcbn.24-194

Heat-killed Lactococcus lactis subsp. lactis L8 ameliorates dextran sulfate sodium-induced colitis in mice

Shogo Kawaguchi 1,2,*, Daisuke Chinda 3, Shinji Ota 2, Akio Tonouchi 4, Hayato Maeda 4, Kazuhide Miura 5, Go Soma 2, Hiroto Hiraga 2, Kayo Ueno 6, Takenori Niioka 6, Mayuki Tachizaki 1, Kazuhiko Seya 1, Tadaatsu Imaizumi 1, Shinsaku Fukuda 2, Hirotake Sakuraba 2
PMCID: PMC12152243  PMID: 40510387

Abstract

Lactococcus lactis subsp. lactis (L. lactis) is a common species of lactic acid bacteria (LAB). There is increasing evidence that probiotic L. lactis ameliorates experimental colitis in mice, whereas few studies have revealed the effects of the paraprobiotics, i.e., inactivated forms of bacteria. L. lactis L8 strain is a newly identified plant-derived LAB. The present study aimed to investigate the effects of heat-killed L. lactis L8 on dextran sulfate sodium (DSS)-induced colitis in mice. C57BL/6J mice were orally administered L. lactis L8 for 12 days. Colitis was induced by adding 3.5% DSS to the drinking water for 7 days. Mice were euthanized on day 12, and colon tissues and fecal samples were collected. Results demonstrated that administration of L. lactis L8 alleviated the clinical score of the colitis and the histological abnormalities. Additionally, L. lactis L8 led to a significant reduction in the level of colon tumor necrosis factor (TNF)-α. Administration of L. lactis L8 did not affect the gut microbial structure, whereas it altered the relative abundance of Clostridiaceae and Rikenellaceae in colitis mice. Our findings suggest that paraprobiotic L. lactis L8 has an immunomodulatory effect on intestinal inflammation in mice, providing important insight into the biological function of L. lactis L8.

Keywords: Lactococcus lactis, dextran sulfate sodium, experimental colitis, TNF-α, gut microbiota

Introduction

Inflammatory bowel diseases (IBD), including ulcerative colitis (UC) and Crohn’s disease (CD), are characterized by chronic relapsing inflammation in the gastrointestinal tract. Although genetical susceptibility and dysregulated gut immune systems are both associated with the onset of IBD, the underlying molecular pathogenesis mechanisms have not been fully identified.(1) Recently, many researchers are focusing on the alteration of the gut microbiome and metabolome in patients with IBD.(2–4) Microbial diversity was decreased in patients with IBD compared to that in healthy subjects.(5,6) Specifically, an increase in potentially pathogenic bacteria [such as Escherichia coli (E. coli), Fusobacterium species, and Ruminococcus gnavus] was observed, whereas the beneficial bacteria such as Lachnospiraceae, Bifidobacterium species, and Faecalibacterium prausnizii decreased.(7) Dysbiosis can influence the regulation of metabolic pathways, including amino acid, short-chain fatty acid (SCFA), and bile acid-related pathways.(8) These changes have been implicated in impaired gut homeostasis and IBD pathogenesis.

Probiotic lactic acid bacteria (LAB) improve the intestinal environment and alleviate enterocolitis symptoms.(9) Although there is little evidence that LAB exerts any therapeutic effects on intestinal inflammation, some probiotic microorganisms may have promising therapeutic potential against IBD. For example, Lactococcus lactis (L. lactis) NCDO2118, Lactobacillus plantarum, Lactobacillus paracasei, and Bifidobacterium breve, improved dextran sulfate sodium (DSS)-induced colitis in a murine model of UC.(10–13) Recently, paraprobiotics, inactivated forms of probiotics, have been a focus of research. They contain a variety of bacterial components, including peptidoglycan, polysaccharide, and cell surface proteins.(14) Paraprobiotics are easy to process and have an immunomodulatory function.(15) For instance, heat-killed Lactobacillus brevis SBC8803 has been shown to exert anti-inflammatory effects in mice with colitis.(16) L. lactis is a common LAB typically found in fermented foods such as dairy products. Many reports have demonstrated that probiotic L. lactis improves DSS-induced colitis.(10,17,18) However, there are few reports on the effects of paraprobiotic L. lactis in DSS-induced colitis.

L. lactis subsp. lactis strain ID5 (L. lactis ID5) and strain L8 (L. lactis L8) are recently identified LAB isolated from the seeds of Fagus crenata and the leaves of Phellodendron amurense, respectively. Our preliminary studies suggested that administration with heat-killed L. lactis L8, but not L. lactis ID5, ameliorated body weight loss and shortening of the colon in colitis mice (Supplemental Methods and Supplemental Fig. 1*). Therefore, the aim of the present study was to investigate the potential of L. lactis L8 to treat DSS-induced colitis in mice to provide insight into the potential applications of the bacteria as a therapeutic method.

Materials and Methods

Materials

The NucleoSpin RNA kit and ThunderbirdTM Next SYBR® qPCR mix were purchased from Macherey-Nagel GmbH and Co. KG (Düren, Germany), and Toyobo (Osaka, Japan), respectively. Moloney murine leukemia virus (M-MLV) reverse transcriptase and oligo (dT)18 primers were purchased from Invitrogen (Carlsbad, CA). The enzyme-linked immunosorbent assay (ELISA) kit for tumor necrosis factor (TNF)-α was purchased from Proteintech (Rosemont, IL).

Preparation of L. lactis L8

L. lactis L8 was isolated from the leaves of Phellodendron amurense, which grows naturally in the Shirakami Mountains of Japan, and stored in a laboratory in the Faculty of Agriculture and Life Science, Hirosaki University. Bacterial culture, heat treatment, and powderization of L. lactis were performed at TOA Biopharma Co., Ltd. (Tokyo, Japan). L. lactis L8 was cultivated at 37°C in modified de Man, Rogosa, and Sharpe (MRS) broth. After harvest by centrifugation, we calculated the number of the bacteria using turbidity measurement, and this was followed by heat treatment at 90°C for 10 ‍min. The heat-killed L. lactis L8 was mixed with starch as excipients and then lyophilized. We verified the bacterial number of the product by fluorescent staining using 4',6-diamidino-2-phenylindole (DAPI). Subsequently, the L. lactis L8 powder or starch (vehicle) were microencapsulated to prevent intravital denaturation by digestive fluids and interaction with DSS (Powder-X Co., Tokyo, Japan).

Animal model

C57BL6/J female mice (6 weeks old) were purchased from CLEA Japan (Tokyo, Japan) and maintained in a specific pathogen-free environment with a 12:12 ‍h light/dark cycle at 22°C. Mice were acclimated for one week and then were randomly divided into four groups: vehicle/water, vehicle/DSS, L. lactis L8/water, and L. lactis L8/DSS (n = 11–12/group). L. lactis L8 or vehicle was dissolved in distilled water and administered to the stomach using a feeding needle for 12 days. The bacterial load was estimated by counting to be 1 × 109/mouse/day. Colitis was induced in mice by adding 3.5% DSS (molecular weight, 5 kD; Fujifilm Wako Pure Chemical, Osaka, Japan) to drinking water for 7 days (from day 4 to 11) (Fig. 1A). Body weight of mice was measured daily. The disease activity index (DAI) was calculated as previously described with slight modification.(19) The score was measured by assessing body weight loss (0: less than 1%; 1: 1–5%; 2: 6–10%; 3: 11–15%; 4: more than 15%), stool consistency (0: normal stool; 1: mildly soft stool; 2: very soft stool; 3: watery stool), and bleeding (0: normal color; 1: brown color; 2: reddish color; 3: bloody stool). The DAI score was determined as the sum of these three assessment scores. The mice were euthanized on day 12, and colon tissues and fecal samples were collected. All animal experiments were conducted in accordance with the Hirosaki University Guidelines for Animal Experimentation.

Fig. 1.

Fig. 1.

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The effect of Lactococcus lactis subsp. lactis strain L8 (L. lactis L8) on dextran sulfate sodium (DSS)-induced colitis in mice. (A) Experimental design. Heat-killed L. lactis L8 or the vehicle was administered to mice for 12 days. Colitis was induced by adding 3.5% DSS to drinking water for 7 days (from day 4 to 11). (B) Bar graph depicting the colon length of mice. Data are presented as mean ± SD, and n = 11–12 in each group. ***p<0.001, *p<0.05, n.s., not statistically significant. (C) Percentage body weight of mice. Data are presented as mean ± SD, and n = 11–12 in each group. *p<0.05. (D) Time course of the disease activity index score. Data are presented as mean ± SD, and n = 5–6 in each group. ***p<0.001, *p<0.05.

Histological analysis

Colon tissues were fixed in 10% formalin and embedded in paraffin. Paraffin blocks were cut into 4–5 ‍μm sections and stained with hematoxylin and eosin (H&E). Histological damage was scored given based on inflammation (0: none; 1: slight; 2: moderate; 3: severe), extent of damage (0: none; 1: mucosa; 2: mucosa and submucosa; 3: transmural), crypt damage (0: none; 1: basal 1/3 damaged; 2: basal 2/3 damaged; 3: only surface epithelium intact; 4: entire loss of crypt and epithelium), and percentage of colitis area (1: 1–25%; 2: 26–50%; 3: 51–75%; 4: 76–100%), as previously described.(20,21)

Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR)

Total RNA was extracted from colon tissues using the NucleoSpin RNA kit according to the manufacturer’s instructions. Single-stranded complementary DNA (cDNA) was synthesized using oligo (dT)18 primers and M-MLV reverse transcriptase. qRT-PCR was performed on a Bio-Rad CFX real-time PCR thermocycler using ThunderbirdTM Next SYBR® qPCR mix. The primer sequences used for amplifying target genes were as follows: TNF-α-F: 5'-GATCTCAAAGACAACCAACATGTG-3', R: 5'-CTCCAGCTGGAAGACTCCTCCCAG-3', Interleukin (IL)-6-F: 5'-GGCCTTCCCTACTTCACAAG-3', R: 5'-ATTTCCACGATTTCCCAGAG-3', IL-17A-F: 5'-GCTCCAGAAGGCCCTCAGA-3', R: 5'-AGCTTTCCCTCCGCATTGA-3', IL-10-F: 5'-TGGCCCAGAAATCAAGGAGC-3', R: 5'-CAGCAGACTCAATACACACT-3', transforming growth factor (TGF)-β-F: 5'-TACCATGCCAACTTCTGTCTGGGA-3', R: 5'-ATGTTGGACAACTGCTCCACC-3', glyceraldehyde 3-phosphate dehydrogenase (GAPDH)-F: 5'-TGAAGGTCGGTGTGAACGGATTTGG-3', R: 5'-ACGACATACTCAGCACCAGCATCAC-3'. Results were normalized to GAPDH mRNA levels. Relative gene expression was calculated using the delta-delta CT method. All assays were performed in triplicates.

ELISA

Total protein was extracted from the colon tissues using RIPA buffer containing a 0.2% proteinase inhibitor cocktail, and the concentration was determined using a BCA protein assay kit (Thermo Fisher Scientific, Waltham, MA). Colon TNF-α levels were measured using an ELISA kit, according to the manufacturer’s instructions.

Gut microbiota analysis

Fecal samples were collected from mice and stored at −80°C until analysis. The gut microbiota analysis was performed at the Bioengineering Lab. Co., Ltd. (Kanagawa, Japan). Total DNA was extracted using a Lab-Aid824s DNA extraction kit (Zeesan, Xiamen, China). The DNA library was constructed using a two-step tailed PCR method. The V3 to V4 regions of the 16S ribosomal RNA (rRNA) genes were amplified using the primers 341F (5'-ACACTCTTTCCCTACACGACGCTCTTCCGATCT-NNNNN-CCTACGGGNGGCWGCAG-3') and 805R (5'-GTGACTGGAGTTCAGACGTGTGCTCTTCCGATCT-NNNNNGACTACHVGGGTATCTAATCC-3'). The PCR products were subjected to a second PCR employing the index primer set F: 5'-AATGATACGGCGACCACCGAGATCTACAC-Index2-ACACTCTTTCCCTACACGACGC-3', R: 5'-CAAGCAGAAGACGGCATACGAGAT-Index1-GTGACTGGAGTTCAGACGTGTG-3'. Amplicons were sequenced using the 2 × 300-bp paired-end method on a MiSeq system (Illumina, San Diego, CA). The microbiome analysis was performed using QIIME2 (ver. 2022.8). Microbial α-diversity was evaluated using the Shannon index. β-Diversity was determined based on the unweighted UniFrac distance and visualized via principal coordinate analysis (PCoA). Statistical significance was analyzed using pairwise permutational multivariate analysis of variance (PERMANOVA). Linear discriminant analysis effect size (LEfSE) was used to analyze the significant difference between two groups. The default linear discriminant analysis (LDA) score threshold was set to 3.5.

Measurements of luminal SCFAs concentration

The SCFAs present in the murine cecal contents were extracted using a previously described method.(22) The acetate, propionate, and n-butyrate concentrations were measured using liquid chromatography-tandem mass spectrometry (LC-MS-MS). The LC-MS-MS analysis was performed using an ACQUITY UPLC I-Class with an ACQUITY UPLC HSS C18 Column (100 Å, 1.8 ‍μm, 2.1 mm × 100 ‍mm) (Waters Co., Midford, MA).

Statistical analysis

Data were presented as mean ± SD. Two-tailed t test and one-way analysis of variance (ANOVA) followed by a Tukey’s post-hoc test were performed to analyze statistical differences between two and four groups, respectively. Statistical significance was set at p<0.05.

Results

L. lactis L8 ameliorated DSS-induced colitis

We first analyzed the effect of L. lactis L8 on DSS-induced colitis. In terms of gross appearance, colon length in the vehicle/DSS mice was significantly reduced compared to that in the vehicle/water mice, while colon length in the L. lactis L8/DSS mice was significantly greater than that in the vehicle/DSS mice (Fig. 1B). The body weight started decreasing 5 days after DSS initiation (Fig. 1C). The weight loss in the L. lactis L8/DSS mice was milder than that in the vehicle/DSS mice (Fig. 1C). Moreover, the DAI score in the L. lactis L8/DSS mice was significantly lower than that in the vehicle/DSS mice (Fig. 1D). Histological analysis revealed that the administration of L. lactis L8 did not result in any colon mucosal damage (Fig. 2A and B). Severe inflammation characterized by loss of epithelial crypts, extensive mucosal ulceration, and marked infiltration of inflammatory cells, was observed to a greater extent in the vehicle/DSS mice compared to that in the vehicle/water group (Fig. 2A and C). On the other hand, mild to moderate histological damage was observed in the L. lactis L8/DSS group compared to that in the vehicle/DSS group (Fig. 2C–E).

Fig. 2.

Fig. 2.

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Impact of L. lactis L8 administration on the histological findings in DSS-induced colitis. H&E staining of the colon sections from mice in the (A) vehicle/water, (B) L. lactis L8/water, (C) vehicle/DSS, and (D) L. lactis L8/DSS groups. Original magnification: 200×. (E) Calculated histological scores. Data are presented as mean ± SD, and n = 9–12 in each group. *p<0.05.

L. lactis L8 reduced the expression level of TNF-α in colitis mice

The expression of cytokines, including TNF-α, IL-6, IL-17A, IL-10, and TGF-β, was evaluated in mice colon tissues of different groups by measuring the mRNA levels. Significantly higher TNF-α mRNA levels were observed in the colitis than those in the non-colitis group, while L. lactis L8 significantly reduced TNF-α mRNA levels in mice with colitis (Fig. 3A). Additionally, L. lactis L8 administration decreased IL-6 and IL-17A levels (Fig. 3A). No significant difference in the mRNA levels of IL-10 or TGF-β between the four groups was observed (Fig. 3A). To clarify whether L. lactis L8 decreased TNF-α at the protein level, we performed ELISA using colon tissue homogenates. Results revealed that the concentration of TNF-α was significantly higher in the vehicle/DSS group than that in the vehicle/water group, and that administration of L. lactis L8 resulted in a significant reduction in TNF-α (Fig. 3B).

Fig. 3.

Fig. 3.

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Impact of L. lactis L8 administration on the expression level of TNF-α. (A) Diagrammatic representations of qRT-PCR performed to analyze the mRNA levels of TNF-α, IL-6, IL-17A, IL-10, and TGF-β. n = 3–5 in each group. (B) Protein levels of TNF-α in murine colon tissues measured by ELISA. The results are presented as mean ± SD, and n = 4–6 in each group. ***p<0.001, *p<0.05, n.s., not statistically significant.

L. lactis L8 did not affect the gut microbial structure

16S rRNA gene sequencing was carried out using fecal samples to elucidate whether the effects of L lactis L8 were accompanied by alterations in the gut microbial composition. Firmicutes and Bacteroidetes are major bacterial phyla in non-colitis groups; the relative abundance of Firmicutes was decreased, and that of Proteobacteria was prominently increased, in the colitis groups (Fig. 4A). At the family level, the main constituent bacteria in the non-colitis groups were Lactobacillaceae and Bacteroidaceae (Fig. 4B). The microbial structure was drastically altered in those colitis groups in which the dominant bacteria belonged to the Enterobacteriaceae family (Fig. 4B). The PCoA revealed that the gut microbial structure in colitis mice was markedly different from that in non-colitis mice (Fig. 4C). The microbial structure in L. lactis L8/DSS was slightly different from that in vehicle/DSS, but this difference was not statistically significant (p = 0.207). The Shannon index showed a tendency to increase in the L. lactis L8/DSS group compared to that in the vehicle/DSS group, but this was also not significant (Fig. 4D).

Fig. 4.

Fig. 4.

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Results of 16S rRNA gene sequencing of fecal samples collected from mice. (A) Relative abundance of microbiota at the phylum level. (B) Relative abundance of microbiota at the family level. (C) Principal coordinate analysis (PCoA) based on the unweighted UniFrac distance. (D) Shannon index α-diversity. Data are presented as mean ± SD, and n = 5 in each group. **p<0.01, n.s., not statistically significant.

The results of LEfSE revealed that the relative abundances of Clostridiaceae and Rikenellaceae in L. lactis L8/DSS were higher and lower than those in the vehicle/DSS group, respectively (Fig. 5A–C). Because alterations in the gut microbial composition affect the amount of metabolites in the intestinal tract, the concentration of SCFAs in the cecal contents was analyzed. The results of LC-MS-MS analysis showed that the luminal butyrate concentration in the L. lactis L8/water group was higher than that in the vehicle/water group, but the difference was not statistically significant (Fig. 5D). The concentration of acetate and propionate in the L. lactis L8/water group was comparable to that in vehicle/water group (Fig. 5E and F). The concentration of SCFAs in both the vehicle/DSS and L. lactis L8/DSS groups was below the measurement threshold.

Fig. 5.

Fig. 5.

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Significant difference in the abundance of the bacterial taxa. Relative abundance of Clostridiaceae and Rikenellaceae were increased and decreased, respectively, in the L. lactis L8/DSS group compared to those in vehicle/DSS group (A–C). The luminal concentration of (D) n-butyrate, (E) acetate, and (F) propionate in the cecal contents was measured using liquid chromatography-tandem mass spectrometry. Data are presented as mean ± SD, and n = 5 in each group. n.s., not statistically significant.

Discussion

We demonstrated that heat-killed L. lactis L8 alleviates intestinal mucosal damage in mice with DSS-induced colitis. The severity of the inflammatory cell infiltration was moderate in the L. lactis L8/DSS compared to that in the vehicle/DSS mice group. TNF-α expression was upregulated in the colon of DSS-treated mice, reflecting the observed histological inflammation, while administration of L. lactis L8 significantly reduced the abnormal level of TNF-α. L. lactis subsup. cremoris FC has been reported to improve DSS-induced colitis and result in decreased levels of TNF-α.(23) Moreover, L. lactis NCDO2118 suppresses colitis and the colon TNF-α expression levels by increasing the population of regulatory T cells in the mesenteric lymph nodes and spleen.(10) In the present study, L. lactis L8 ameliorated the histological abnormalities and the level of TNF-α, which is a pleiotropic cytokine with a key role in the molecular pathogenesis of chronic colitis. This inflammatory cytokine is considered to be an important therapeutic target, with biological therapy against this molecule being highly effective for patients with IBD. Consequently, results of the present study provide the basis for future studies on the use of L. lactis L8 as an immunomodulator for intestinal inflammation. We could not identify the exact mechanism by which L. lactis L8 decreased the level of TNF-α, and the future research will be needed to elucidate this phenomenon.

Probiotic LAB prevent enterocolitis by both inhibiting pathogenic bacterial growth and boosting host immunity. Although the ability of heat-killed bacteria to directly change gut microbiota composition is under debate, accumulating evidence suggests they improve colitis through gut microbiota modulation. Feng et al. reported that significantly increased Lactobacillus populations were found in Bifidobacterium bifidum B1628-treated mice.(24) Kye et al.(25) reported that supplementation with heat-killed Lactobacillus acidophilus PIN7 restored the proportion of Proteobacteria in DSS colitis mice. These reports suggest that heat-killed LAB modulates the gut microbial structure. In DSS-treated mice, gut dysbiosis has been detected, and it is similar to that detected in patients with IBD.(26) An increased abundance of E. coli, Bacteroides, and Helicobacter has been observed in mice with colitis.(27) In the present study, we confirmed that Enterobacteriaceae was increased in DSS-treated mice, while L. lactis L8 administration did not change the ratio of potentially harmful microbes. On the other hand, supplementation with L. lactis L8 altered the relative abundance of Clostridiaceae and Rikenellaceae. Clostridium species normally inhabit the intestines of humans and other animals. Three major species of Clostridium (C. difficile, C. coccides, and C. leptum) are associated with human UC.(28) C. difficile causes colitis as a result of microbial substitution, whereas the other two species maintain gut homeostasis by producing butyrate.(29,30) As L. lactis L8 increased the abundance of different species from the well-known Clostridiaceae, we could not clarify the significance of the change. Since Schwab et al.(31) reported that the ratio of Clostridiales to Bacteroidales increases during the healing stage of DSS-induced colitis, we speculate that the increase of Clostridiales might be involved in the recovery of mucosal damage. Furthermore, we have found that administration of L. lactis L8 causes the decreased occupancy of Rikennellaceae. Gu et al.(32) reported that Rikennellaceae is positively correlated with the expression of IFN-γ in DSS-treated mice. As IFN-γ has a pathogenetic role in IBD,(33,34) the decreased ratio of Rikennellaceae might be associated with inflammation relief.

In conclusion, our results demonstrated that the heat-killed L. lactis L8 alleviates DSS-induced colitis accompanied with the alteration of the relative abundance of Rikenellaceae and Clostridiaceae. These findings provide insight and a basis for future studies on the use of L. lactis L8 as a potential treatment for intestinal inflammation.

Data Availability Statement

The sequence data are available in the DDBJ Sequenced Read Archive using the accession numbers DRR483913-483932 (https://ddbj.nig.ac.jp/resource/bioproject/PRJDB16032).

Acknowledgments

This study was supported by the JSPS KAKENHI Grant Number 24K11143 and the Project for Enhancing the Environment to Create Innovation in Regional Core Universities. We would like to thank Editage (www.editage.com) for English language editing.

Conflict of Interest

No potential conflicts of interest were disclosed.

Supplementary Material

Supplemental Methods (15.9KB, pdf)
Supplemental Fig. 1 (68.2KB, pdf)

References

  • 1.Khor B, Gardet A, Xavier RJ. Genetics and pathogenesis of inflammatory bowel disease. Nature 2011; 474: 307–317. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 2.Manichanh C, Borruel N, Casellas F, Guarner F. The gut microbiota in IBD. Nat Rev Gastroenterol Hepatol 2012; 9: 599–608. [DOI] [PubMed] [Google Scholar]
  • 3.Ahmed I, Roy BC, Khan SA, Septer S, Umar S. Microbiome, metabolome and inflammatory bowel disease. Microorganisms 2016; 4: 20. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 4.Gallagher K, Catesson A, Griffin JL, Holmes E, Williams HRT. Metabolomic analysis in inflammatory bowel disease: a systematic review. J Crohns Colitis 2021; 15: 813–826. [DOI] [PubMed] [Google Scholar]
  • 5.Hansen R, Thomson JM, El-Omar EM, Hold GL. The role of infection in the aetiology of inflammatory bowel disease. J Gastroenterol 2010; 45: 266–276. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 6.Matsuoka K, Kanai T. The gut microbiota and inflammatory bowel disease. Semin Immunopathol 2015; 37: 47–55. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 7.Sartor RB, Wu GD. Roles for intestinal bacteria, viruses, and fungi in pathogenesis of inflammatory bowel diseases and therapeutic approaches. Gastroenterology 2017; 152: 327–339.e4. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 8.Upadhyay KG, Desai DC, Ashavaid TF, Dherai AJ. Microbiome and metabolome in inflammatory bowel disease. J Gastroenterol Hepatol 2023; 38: 34–43. [DOI] [PubMed] [Google Scholar]
  • 9.Kato K, Mizuno S, Umesaki Y, et al. Randomized placebo-controlled trial assessing the effect of bifidobacterial-fermented milk on active ulcerative colitis. Aliment Pharmacol Ther 2004; 20: 1133–1141. [DOI] [PubMed] [Google Scholar]
  • 10.Luerce TD, Gomes-Santos AC, Rocha CS, et al. Anti-inflammatory effects of Lactococcus lactis NCDO2118 during the remission period of chemically induced colitis. Gut Pathog 2014; 6: 33. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 11.Zhang F, Li Y, Wang X, Wang S, Bi D. The impact of Lactobacillus plantarum on the gut microbiota of mice with DSS-induced colitis. Biomed Res Int 2019; 2019: 3921315. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 12.Chen CL, Hsu PY, Pan TM. Therapeutic effects of Lactobacillus paracasei subsp. paracasei NTU101 powder on dextran sulfate sodium-induced colitis in mice. J Food Drug Anal 2019; 27: 83–92. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 13.Chen Y, Jin Y, Stanton C, et al. Alleviation effects of Bifidobacterium breve on DSS-induced colitis depends on intestinal tract barrier maintenance and gut microbiota modulation. Eur J Nutr 2021; 60: 369–387. [DOI] [PubMed] [Google Scholar]
  • 14.Aguilar-Toalá JE, Garcia-Varela R, Garcia HS, et al. Postbiotics: an evolving term within the functional foods field. Trends in Food Sci Technol 2018; 75: 105–114. [Google Scholar]
  • 15.Lee NK, Park YS, Kang DK, Paik HD. Paraprobiotics: definition, manufacturing methods, and functionality. Food Sci Biotechnol 2023; 32: 1981–1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 16.Ueno N, Fujiya M, Segawa S, et al. Heat-killed body of lactobacillus brevis SBC8803 ameliorates intestinal injury in a murine model of colitis by enhancing the intestinal barrier function. Inflamm Bowel Dis 2011; 17: 2235–2250. [DOI] [PubMed] [Google Scholar]
  • 17.Liu M, Zhang X, Hao Y, et al. Protective effects of a novel probiotic strain, Lactococcus lactis ML2018, in colitis: in vivo and in vitro evidence. Food Funct 2019; 10: 1132–1145. [DOI] [PubMed] [Google Scholar]
  • 18.Alves JL, Lemos L, Rodrigues NM, et al. Immunomodulatory effects of different strains of Lactococcus lactis in DSS-induced colitis. Braz J Microbiol 2023; 54: 1203–1215. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 19.Vasina V, Broccoli M, Ursino MG, et al. Non-peptidyl low molecular weight radical scavenger IAC attenuates DSS-induced colitis in rats. World J Gastroenterol 2010; 16: 3642–3650. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 20.Chelakkot C, Ghim J, Rajaselaran N, et al. Intestinal epithelial cell-specific deletion of PLD2 alleviates DSS-induced colitis by regulating occluding. Sci Rep 2017; 7: 1573. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 21.Dieleman LA, Palmen MJ, Akol H, et al. Chronic experimental colitis induced by dextran sulphate sodium (DSS) is characterized by Th1 and Th2 cytokines. Clin Exp Immunol 1998; 114: 385–391. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 22.Tomoda K, Kubo K, Asahara T, et al. Cigarette smoke decreases organic acids levels and population of bifidobacterium in the caecum of rats. J Toxicol Sci 2011; 36: 261–166. [DOI] [PubMed] [Google Scholar]
  • 23.Nishitani Y, Tanoue T, Yamada K, et al. Lactococcus lactis subsp. cremoris FC alleviates symptoms of colitis induced by dextran sulfate sodium in mice. Int Immunopharmacol 2009; 9: 1444–1451. [DOI] [PubMed] [Google Scholar]
  • 24.Feng C, Zhang W, Zhang T, et al. Heat-killed Bifidobacterium bifidum B1628 may alleviate dextran sulfate sodium-induced colitis in mice, and the anti-inflammatory effect is associated with gut microbiota modulation. Nutrients 2022; 14: 5233. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 25.Kye YJ, Lee SY, Kim HR, et al. Lactobacillus acidophilus PIN7 paraprobiotic supplementation ameliorates DSS-induced colitis through anti-inflammatory and immune regulatory effects. J Appl Microbiol 2022; 132: 3189–3200. [DOI] [PubMed] [Google Scholar]
  • 26.Nagalingam NA, Kao JY, Young VB. Microbial ecology of the murine gut associated with the development of dextran sodium sulfate-induced colitis. Inflamm Bowel Dis 2011; 17: 917–926. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 27.Zhang Y, Si X, Yang L, Wang H, Sun Y, Liu N. Association between intestinal microbiota and inflammatory bowel disease. Animal Model Exp Med 2022; 5: 311–322. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 28.Zhang SL, Wang SN, Miao CY. Influence of microbiota on intestinal immune system in ulcerative colitis and its intervention. Front Immunol 2017; 8: 1674. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 29.Louis P, Flint HJ. Diversity, metabolism and microbial ecology of butyrate-producing bacteria from the human large intestine. FEMS Microbiol Lett 2009; 294: 1–8. [DOI] [PubMed] [Google Scholar]
  • 30.Atarashi K, Tanoue T, Shima T, et al. Induction of colonic regulatory T cells by indigenous Clostridium species. Science 2011; 331: 337–341. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 31.Schwab C, Berry D, Rauch I, et al. Longitudinal study of murine microbiota activity and interactions with the host during acute inflammation and recovery. ISME J 2014; 8: 1101–1114. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 32.Gu W, Zhang L, Han T, Huang H, Chen J. Dynamic changes in gut microbiome of ulcerative colitis: initial study from animal model. J Inflamm Res 2022; 15: 2631–2647. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 33.Ito R, Shin-Ya M, Kishida T, et al. Interferon-gamma is causatively involved in experimental inflammatory bowel disease in mice. Clin Exp Immunol 2006; 146: 330–338. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 34.Neurath MF. Cytokines in inflammatory bowel disease. Nat Rev Immunol 2014; 14: 329–342. [DOI] [PubMed] [Google Scholar]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

Supplemental Methods (15.9KB, pdf)
Supplemental Fig. 1 (68.2KB, pdf)

Data Availability Statement

The sequence data are available in the DDBJ Sequenced Read Archive using the accession numbers DRR483913-483932 (https://ddbj.nig.ac.jp/resource/bioproject/PRJDB16032).

Articles from Journal of Clinical Biochemistry and Nutrition are provided here courtesy of The Society for Free Radical Research Japan

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