CYP21A1 promotes the proliferation of chicken granulosa cells and inhibits the apoptosis of chicken granulosa cells. The qRT-PCR results of the CYP21A1 after the overexpression or interference of CYP21A1(A, B). The chicken granulosa cells proliferation curves were measured with CCK-8 assay after the overexpression or repression of CYP21A1(C, D). Flow cytometry results of annexin V-FITC/PI staining of the chicken granulosa cells after CYP21A1 overexpression or interference (E, F, H, I). The apoptosis rate of chicken granulosa cells after the overexpression or repression of CYP21A1 (G, J). Data are presented as mean ± SEM. *P < 0.05, **P < 0.01.