Supplementary Material for: Mild Synovitis Impairs Chondrogenic Joint Environment

The impact of mild synovitis on the chondrogenic environment in the joint pertaining to cartilage repair is often neglected. In this study, 21 synovial samples were collected from foot surgeries, for histology and isolation of fibroblast-like synoviocytes (FLS). Of the 21 samples, 13 were normal and eight mild synovitis according to their synovitis scores. In mild synovitis, CD3+lymphocytes were increased in the sublining layer. When chondrocytes were cultured and treated with the conditioned medium produced by FLS, their glycosaminoglycan production was negatively correlated with the synovitis scores of the synovium, from which FLS were isolated. In conclusion, mild synovitis in common joint conditions compromises the process of chondrogenesis, via inhibiting chondrocyte matrix production by FLS. The results suggest that the concomitant synovitis, even being mild, could significantly alter the joint environment for chondrogenesis and impair the outcome of cartilage repair.