Figure 5.

Interleukin 6 (IL-6)–treated chondrocytes increases matrix degradation regulated by estrogen-related receptor γ (ERRγ). (A) Non-transfected cells (control group) or cells transiently transfected with the control small interfering RNA (siRNA) (Con-siRNA) or ERRγ-siRNAs were cultured in the presence of IL-6. The Western blot assays showed decreased levels of ERRγ in mandibular condylar chondrocytes (MCCs) transfected with ERRγ-specific siRNAs (n = 3). (B) Western blotting show that IL-6-induced increases in matrix metalloproteinase 9 (MMP9) and vascular endothelial growth factor A (VEGFA) were abrogated in ERRγ-knockdown cells and IL-6-induced decreases in COL2 and AGG were reversed by ERRγ-siRNAs (n = 3). (C) and (D) Toluidine blue staining results of MCCs transfected with 20 nM Con-siRNA or 20 nM ERRγ-siRNA and stimulated by 20 ng/ml IL-6 for 12 h (n = 3). (E) ERRγ knockdown enhanced the proliferation of MCCs in medium containing 20 ng/ml IL-6, as determined by CCK-8 assays (n = 3). All experiments were performed in triplicate, and the results are expressed as the mean ± SD. *P < 0.05; **P < 0.01. Scale bar: 50 μm.