BAX and polycystic ovary syndrome: We assessed apoptotic protein family (including cleaved caspase-3, Bax and Bcl-2) expression, mitochondrial membrane potential, and TUNEL staining to assess early, middle and late-stage apoptosis [42, 43], as early and late apoptosis of granulosa cells is an important pathological factor in abnormal follicular development related to PCOS.