MMP2 and rheumatoid arthritis: However, the other study indicated that MMP-2 suppresses RA synovial fibroblast-mediated cartilage degradation; MMP-2 KO mice developed arthritis of greater clinical and histological severity than wild-type mice (46). Therefore, the role of MMP2 in the progression of RA-FLS is still controversial. We speculate that the varied roles of MMP2 in the progression of RA may be associated with the inconsistency of microenvironment and experimental conditions.