Background: Osteoarthritis (OA) is a common degenerative disease of joints and the main cause of elder patients' disability. Cartilage damage is a major problem in OA. To investigate the pathogenesis of OA, this study aimed to analyze the differential proteomics of chondrocytes in OA patients compared to normal chondrocytes.

Materials and Methods: Protein extracts of cartilages prepared from 7 patients with end-stage OA, who were candidates for arthroplasty, were compared to 7 samples from normal cartilages. Proteins were analyzed by fluorescent gel electrophoresis (2D-DIGE) method and the differentially expressed proteins were identified by mass spectrometry (MS). Two samples were lost because of tissue insufficiency and the other because of mistransportation.

Results: Among the 25 analyzed proteins, difference was seen for the 8 following proteins: osteonectine, cathepsin, chondroadherin, HSP, clustrine and collagen II, Activin A and carbonic Anhydrase. The levels of osteonectine, cathepsin, clustrine and collagen II were decreased in the OA samples compared to normal chondrocytes. Moreover, the levels of chondroadherin and Activin A were increased in the OA samples compared to normal chondrocytes.

Conclusion: The findings demonstrate the ability of the 2D-DIGE/MS platform to identify proteins with altered expression in chondrocytes of patients with OA. The identification of these proteins may open new lines of research for the pathogenesis of OA.