Figure 3. BMP5 regulates in vivo and in vitro chondrocyte catabolism. (A) QRT-PCR assay results show mRNA expression levels of pro-inflammatory cytokines (TNF-α, IL-1β), anabolic factors (type II collagen and SOX9), and catabolic factors (MMP13 and ADAMTS-5) in control and BMP-knockdown murine chondrocytes, treated with IL-1β or not. (B) Representative western blots show expression levels of MMP13, Runx2, and Col2 proteins in control and BMP-knockdown murine chondrocytes. (C) Representative immunohistochemical images and (D) quantitative analyses of the IHC results show MMP13, Col2a, and TIMP2 expression in the knee articular cartilage sections from sham-operated, DMM plus LV-siNC, and DMM plus LV-siBMP5 groups of mice at 4 weeks post-DMM operation. All data are represented as means ± SD (n=5 per group).