Protein Expression Profile of Synovial Fibroblasts in Experimental Post-traumatic Arthritis

ABSTRACT

OBJECTIVE: To evaluate and compare protein expression profiles of synovial fibroblasts using proteome analysis in swine knee injuries with joint instability, during early post-traumatic arthritis (PTA) development. METHOD: Experimental PTA was induced by transection of the anterior cruciate ligament (ACL) in swine left knee joints. After sacrifice at 8 weeks, cartilage and synovium obtained from both knee joints were prepared for histopathologic examination. Cultured synovial fibroblasts were processed for 2-dimensional electrophoresis and mass spectrometric analysis. Histopathologic examination showed overt arthritic changes that supported the development of early PTA. RESULTS: Proteome analyses led to the identification of more than 1,500 protein spots and of 11 differently expressed protein spots. Of those, six proteins were down-regulated (cytoskeletal beta actin, cofilin-1, destrin, Rho GDP dissociation inhibitor alpha, and unnamed protein product), and five proteins were up-regulated (alpha-B crystallin, smooth muscle protein 22-alpha, and cytoskeletal beta actin) in ACL-transected synovial fibroblasts. That is, proteins related to cellular organization and signal transduction are down-regulated, and those related to cell rescue, defence, and stress are up-regulated. CONCLUSION: These results may suggest that joint instability contributes to the development of PTA and is one of the major etiologic factors of PTA. In addition, this suggests that the proteome analysis of synovial fibroblasts is a useful approach in examining a joint after an injury and can be used to understand the pathogenesis of PTA.