Table 1.

In vitro models for blood-induced arthropathy studies.

	Reference	Experimental Design	Research Findings
CARTILAGE	Convery et al., 1976 [55]	Biochemical and biomechanical analyses of mongrel dogs subject to continuous hemarthrosis [55]	Significant decrease in GAG content observed as early as 4 weeks. Total collagen content was not significantly affected until after 12 and 16 weeks. Experimental cartilage lost significant amount of mechanical integrity as a result of continuous hemarthrosis [55].
	Roosendaal et al., 1999 [52]	Co-culture of human cartilage tissue with RBC or mononuclear cells (MNC) + RBC followed by a 12-day recovery period [52]	Acute MNC + RBC exposure resulted in prolonged dose-dependent inhibition of proteoglycan synthesis and chondrocyte death [52].
	Hooiveld et al., 2003 [9]	Co-culture of human cartilage tissue with whole blood, mononuclear cells + RBC, or caspase inhibitors followed by a 12-day recovery period [9]	After 4-day exposure of blood treatment, apoptosis occurred in chondrocytes. Caspase inhibitors partially restored proteoglycan synthesis after blood exposure [9]
	Hooiveld et al., 2003 [61]	Co-culture of human cartilage tissue with RBC, mononuclear cells + RBC, CD14+ cells + RBC, or lysed RBC with IL-1β followed by a 12-day recovery period [61]	Lysed RBC + IL-1β produced by monocytes inhibited proteoglycan synthesis and increased production of hydrogen peroxide. Hemoglobin-derived iron + hydrogen peroxide resulted in formation of hydroxyl radicals that lead to further chondrocyte damage. DMSO and hydroxyl radicals can restore cartilage proteoglycan synthesis [61].
	Jansen et al., 2007 [72]	Healthy human articular cartilage explants cultured in the presence or absence of varying blood concentrations for different time intervals followed by a 12-day recovery period after withdrawal of blood [72]	50% v/v blood exposure to cartilage led to detrimental effects independent of time. Blood concentration-dependent effects were observed and after 2 days of exposure of at least 10% v/v, effects were irreversible [72].
	van Meegeren et al., 2012 [73]	Human cartilage explants exposed to coagulating and anticoagulated blood, plasma and serum [73]	Exposure of coagulating blood resulted in more damage than anticoagulated blood. In absence of mononuclear cells and RBC, plasma and serum exposure did not alter cartilage matrix turnover [73].
	Huebner et al., 2013 [74]	Gene expression analyses of cartilage from a rabbit bone drill PTOA model [74]	Upregulation of cartilage degradation markers including TGFβ and MMP13, suggesting that intra-articular bone injury contributes to progressive cartilage damage consistent with OA in adult rabbits [74].
	van Meegeren et al., 2013 [7]	Evaluation of biochemical properties of canine explants comparing effects of acute blood exposure vs. intermittent intra-articular blood injections [7]	Explants exposed to acute and micro bleeds saw increased proteoglycan synthesis rates. Release of newly formed GAGs was significantly increased following acute blood exposure [7]
	Bajpayee et al., 2017 [75]	Gene expression and biochemical analysis of rabbit cartilage following intra-articular DEX administration in a rabbit ACL transection model [75]	No significant differences observed in collagen content between ACLT and control. Significant decrease in GAG content observed in cartilage of ACLT in comparison to control. Avidin-DEX treatment suppressed catabolic gene expression and joint swelling significantly more than free DEX treatment [75].
	Yao et al., 2020 [76]	Simulate inflammation and iron overload via administration of IL-1β and ferric ammonium citrate [76]	Under inflammation and iron overload, chondrocytes undergo ferroptosis. Ferroptotic induction via erastin caused increased cartilage degradation enzymes and decreased collagen II expression [76].
	Lee et al., 2023 [11]	Co-culture of human chondrocyte-based tissue engineered cartilage and human chondrocyte monolayer with intact RBC and RBC lysates [11]	Markers of tissue breakdown were observed in cartilage constructs without parallel losses in DNA. Dose-dependent loss of viability observed in chondrocyte monolayers, with greater toxicity observed with lysates; intact RBCs induced changes to lipid profiles and upregulated highly oxidizable fatty acids; RBC lysates induced cell death via ferroptosis [11]
SYNOVIUM	Muirden et al., 1967 [47]	Assess ferritin formation by synovial cells exposed to hemoglobin [47]	Findings suggest that synovial cells release iron from hemoglobin thereby synthesizing apoferritin without other cell intervention [47]
	Roosendaal et al., 1999 [24]	Analysis of catabolic activity of supernatants of synovial tissue after intraarticular blood exposure in canine model [24]	After 4 days of blood exposure, synovial tissue had no significant catabolic activity. After 16 days, synovial tissue had significant cartilage destructive properties. The supernatant of synovial tissue decreased total proteoglycan content and lowered proteoglycan synthesis [24].
	Hooiveld et al., 2004 [69]	Biochemical analysis of synovial fluid of PTOA guinea pig model [69]	Stromal cell-derived factor-1 (SDF-1) and MMP13 synovial fluid concentration were statistically similar between idiopathic and PTOA groups suggesting that other inflammatory factors may be involved [69]
	McCarty et al., 2011 [77]	Characterize composition, coagulation and mechanical properties of blood and synovial fluid mixtures [77]	Dilution of blood with SF decreased mechanical stiffness of the final clot structure, altered coagulation torque profile over time, and increased fluid permeability. In comparison to control, SF had a lesser effect on mechanical properties of clot possibly due to presence of HA [77]
	Ashraf et al., 2011 [78]	Measure synovial inflammation and angiogenesis as a result of meniscal transection in a rat OA model [78]	Synovial inflammation increased 24 h after drug-induced synovitis. Increase of macrophage infiltration and endothelial cell proliferation confirmed synovitis and angiogenesis after meniscal transection. Anti-inflammatory drugs inhibited synovitis and synovial angiogenesis [78].
	Stefani et al., 2019 [79]	Investigation of solute transport measures in bovine tissue-engineered synovium model [79]	NO and hyaluronic acid (HA) secretion of engineered synovium was similar to native synovial tissue. IL-treated engineered synovium displayed characteristics of human OA synovium [79].
	Machado et al., 2019 [80]	Compare effects of blood-derived products and sodium hyaluronate on equine synovial fluid cells from osteochondrotic joint [80]	All treatments decreased production of reactive oxygen species. PRP increased prostaglandin (PG) E2 concentrations and PRP, APP, and IRAP increased IL-1 receptor antagonist proteins [80]
MENISCUS	Heard et al., 2019 [81]	Acute controlled response of meniscal cell to blood and blood + DEX [81]	Autologous blood exposure did not affect meniscal cell viability but blood + DEX treatment reduced cell viability suggesting that meniscal cells may be susceptible to glucocorticoid-mediated apoptosis. [81]
	Betsch et al., 2024 [82]	Porcine explants and primary meniscus cells exposed to various concentrations of whole blood for 3 days to simulate injury [82]	Acute whole blood exposure increased MMP activity. Blood-derived mononuclear leukocytes increased NO release and MMP activity but decreased GAG content suggesting that they activate catabolic pathways that can lead to meniscal degradation. Isolated intact RBC did not affect meniscus catabolism. [82]
BONE	Niikura et al., 2005 [83]	Assess potential of hemarthrosis-derived cells to differentiate into osteoblast-like cells via gene expression and osteoblastic markers [83]	Osteoblastic gene markers significantly increased in hemarthrosis-derived cells in comparison to control and cell morphology was cuboidal shaped. Human hemarthrosis-derived cells contain osteoprogenitor cells and can be used for bone regeneration [83]
	Maerz et al., 2017 [84]	Rats were subjected to noninvasive ACL rupture. Whole blood MSC concentration was assessed using flow cytometry and synovial fluid and serum were assayed for stromal cell-derived factor (SDF-1α) [84]	Following ACL rupture, there was a significant increase in bone marrow-derived MSC concentration and SDF-1α. Cell tracking indicated active recruitment of MSCs to the injured joint. [84]
ACL	Jacobson et al., 2008 [14]	Measure effect of platelets and erythrocytes on cytokine release and scaffold contraction in a 3D fibroblast model [14]	Platelet concentration significantly affects fibroblast proliferation, cytokine release, and gel contraction [14]
	Harrison et al., 2011 [13]	Analyze effect of erythrocyte concentration on wound healing capacity of an ACL fibroblast collagen scaffold [13]	Greater scaffold contraction and fibroblast proliferation of samples with RBC concentrations lower than that in whole blood. Increasing RBC concentration over amount in whole blood stimulates fibroblast collagen production and decreases scaffold contraction. [13]
	Yoshida et al., 2013 [85]	Examine effect of peripheral blood mononuclear cells (PBMCs) on 3D ACL fibroblast collagen scaffold [85]	Co-culture of PBMCs and ACL fibroblasts without presence of platelets had no effect. PBMCs + platelet exposure led to an increase in collagen gene and protein expression as well as increased IL-6 expression. [85]