Figure 6. OPN accelerates the degeneration of OA articular cartilage. (A) Toluidine blue staining of ADTC5 cells treated with ITS (10 μg/mL) followed by stimulation with rmOPN (100 ng/mL) and neutralizing antibody (1.0 μg/mL) for 14 days. Western blot analysis and quantification of the expression of collagen-10 (COL10) and MMP-13 in ADTC5 cells treated with ITS followed by stimulation with rmOPN and neutralizing antibody for 14 days. (B, C) Representative immunostaining and quantitative analysis of COL10+, MMP-13+ cells in articular cartilage of an OA mouse model treated with vehicle, rmOPN or neutralizing antibody, and sham group. Scale bars = 50 μm. Safranin O-fast green staining and OARSI scores of tibial articular cartilage and subchondral bone of an OA mouse model treated with vehicle, rmOPN or neutralizing antibody, and sham group. Scale bars = 200 μm. Data are shown as mean ± s. d. and were analyzed by one-way ANOVA, n=6, *P < 0.05, **P < 0.01.