Figure 4. FOXO4 facilitates TM3 Leydig cell senescence and maintains the viability of senescent cells. (A–E) Western blots revealing that, compared to control, FoxO4 knockdown increases protein levels of p53 and Ser15-phospho-p53 but decreases levels of p21 in senescent TM3 Leydig cells. (F) CCK8 assays showing that FoxO4 knockdown decreases the viability of senescent TM3 Leydig cells. (G, H) Annexin V-FITC/PI apoptosis assays showing that FoxO4 knockdown increases the apoptosis rate among senescent TM3 Leydig cells. NC, negative control. Data presented are representative of three independent experiments. Data depict the mean ± SD. *P<0.05. NS, nonsignificant.