Figure 3.

Curcumin inhibited ER stress in oxidative stress-induced rat chondrocytes. (a-c) The mRNA expression levels of CHOP, GRP78, and ATF4 in each group were examined by real-time PCR analysis. (d, e) Protein expression levels of CHOP, GRP78, and ATF4 were evaluated by western blot analysis. (f) CHOP immunofluorescence staining. Markedly increased red bright puncta indicated the upregulated expression of CHOP (bar: 10 μm). (g) Quantitation of the number of CHOP positive chondrocytes in each group based on immunofluorescence staining. The results represent mean ± standard deviation (n = 5). ^∗ P < 0 05, ^∗∗ P < 0.01. TBHP: tert-Butyl hydroperoxide; CUR: curcumin; TG: thapsigargin.