Figure 4. Effect of ISO on apoptosis. (A, B) Effects of ISO pretreatment on the apoptosis by flow cytometry analysis. (C–E) Effects of ISO pretreatment on the apoptosis pathway by western blotting analysis. (F) Effect of ISO pretreatment on the MMP in H2O2-induced chondrocytes. Red represents high MMP, green represents low MMP. (G–J) Effects of ISO pretreatment on the MAPK pathway by western blotting analysis. Results shown expressed as means ± SD (n = 3). #p < 0.05 compared with control group, *p < 0.05, **p < 0.01 compared with OA group. The H2O2 concentration is 500 μM.