Figure 1. Ast did not affect cell viability and activated Nrf2 in mouse chondrocytes. (A) The cytotoxic effect of Ast (5, 10, 20, 40, and 80 μM) exposure for 24 and 48 h on chondrocytes was determined using a CCK8 assay. (B, C) Chondrocytes were treated with Ast (5, 10, and 20 μM) for 24 h. Expression levels of Cyclin D1, Nrf2, and Keap1 were determined by western blotting and quantified. (D, E) Nuclear translocation of Nrf2 was detected by western blotting and immunofluorescence after treatment of chondrocytes with Ast (10 μM) for 24 h, and the band density of Nrf2 in nucleus was quantified. The nuclear and cytoplasmic fractions used in the western blotting were obtained using a nuclear and cytoplasmic protein extraction kit (P0027, Beyotime, China). The data are presented as dot plots from three independent experiments. Significant differences among different groups are indicated as *p < 0.05 vs. control; **p<0.01 vs. control; ****p<0.0001 vs. control.