Crosstalk of Synovial Fibroblasts and Chondrocytes in Condylar Hyperplasia: An In Vitro Pilot Study

Abstract Objective Increasing evidence indicates an interaction between synovium and cartilage in the temporomandibular joint (TMJ) and other joints. We recently demonstrated that the expression of proangiogenic factors was enhanced, and that of factors promoting matrix degradation was decreased in synovial fibroblasts of condylar hyperplasia (CH). The aim of this study was to explore whether CH chondrocytes can affect the expression of these factors of synovial fibroblasts ໿in a coculture system. Study Design The expression of VEGF, CD34, FGF-2 and TIMP1 from CH condylar tissues was observed by immunohistochemical methods. Synovial fibroblasts of control tissues were cocultured with chondrocytes of CH, and the protein expression of VEGF, FGF-2, TSP1, MMP3 and TIMP1 was examined by western blotting. Results Positive staining for VEGF, CD34, FGF-2 and TIMP1 was found in the hypertrophic cartilage layer of CH condylar tissues. The protein expression of VEGF, FGF-2 and TIMP1 was significantly increased in cocultured synovial fibroblasts, but TSP1 and MMP3 expression was decreased. Conclusions The angiogenic factors and matrix degradation-related factors in synovial fibroblasts cocultured with CH chondrocytes showed the same trends as those in synovial fibroblasts from CH tissue, which suggests potential crosstalk between synovial fibroblasts and chondrocytes during CH progression.