Altered expression of aggrecan, FAM20B, B3GALT6, and EXTL2 in patients with osteoarthritis and Kashin-Beck disease

Abstract Background: Kashin-Beck disease (KBD) is an endemic osteoarticular disease, which has had a high prevalence in China. Osteoarthritis (OA) is the dominating proportion of osteoarticular disease. The objective of this study is to investigate the expression of enzymes involved in synthesis and modification of chondroitin sulfate (CS) in knee cartilage tissue of osteoarthritis (OA) and Kashin-Beck disease (KBD) patients. Methods: Knee articular cartilage samples were obtained from 18 age and gender matched donors. Hematoxylin & eosin staining, toluidine blue staining, and immunehistochemical staining were performed to estimate the expression level and localization of aggrecan and the enzymes associated with CS synthesis and modification (FAM20B, GalT-II, EXTL2). Rank-based analyses of variance (ANOVA) test was used for the multiple comparisons of discrepancy in the positive staining rate among the KBD, OA, and control groups. Results: Decreased proteoglycans were observed in OA and KBD compared with control group. In line with these expression trends, the positive staining rates of aggrecan were lower in KBD and OA group than control group. The positive staining rates of CS chain modifying enzymes FAM20B, GalT-II, and EXTL2 were also decreased in OA and KBD group. Conclusion: In conclusion, our study uncovered that the enzymes involved in synthesis and modification of CS can influence the expression synthesis of aggrecan and CS. Further investigation of these enzymes can provide new theoretical and experimental targets for OA and KBD pathogenesis studies.