| Objective To determine the effect of Wnt-β-catenin pathway on the process of osteoarthritis (OA) by quantifying the expression of β-catenin and sclerostin (SOST) in the cartilage and subchondral bone in OA patients at different disease stage. Methods All the cartilage and subchondral bone samples were obtained from OA patients undergoing total knee arthroplasty (TKA, n=39) and patients undergoing amputation due to lower extremity injury (n=6). Cartilage and adjacent subchondral bone isolated from medial tibial plateau were stained with Safranin O. Modified Mankin score was used for classified the stage of the samples. The samples were then divided into normal group, mid-stage OA group, and end-stage OA group. Immunohistochemistry was used to quantify the expression of β-catenin and SOST in the 3 groups. Results According to the modified Mankin score, 6 samples were normal, 14 were mid-stage OA, and 25 samples were end-stage OA, of the 45 samples. The percentage of β-catenin staining positive cells in cartilage was 17% in normal group, 49% in mid-stage OA group, and 62% in end-stage OA group, and in subchondral bone was 59% in mid-stage OA group, 11% in normal group, and 12% in end-stage group, respectively. The percentage of SOST staining positive cells in the cartilage was the highest in mid-stage OA group (59%), but less in normal group (11%) and end-stage OA group (12%). The percentage of positive staining cells in subchondral bone was 58% in normal group, 38% in mid-stage OA group, and 16% of end-stage OA group, respectively. Conclusion The expressions of β-catenin and SOST are associated with the development of OA, suggesting that Wnt-β-catenin signaling pathway plays an important role in the process of OA. |