Background/aims: Abnormal apoptosis of granulosa cells (GCs) is thought to involve in the pathogenesis of polycystic ovary syndrome (PCOS); however, the associated cellular and molecular mechanisms remain unclear.
Methods: Primary GCs were obtained from healthy women and women with PCOS. The cell proliferation and apoptosis were analyzed in insulin-stimulated and insulin receptor gene (INSR) siRNA-transfected GCs. The protein expression of Akt-mTOR-S6K1 signal molecules was measured by Western blot.
Results: This study showed that 1 nM of insulin significantly stimulated cell proliferation, induced cell apoptosis, and decreased the telomerase activity in GCs from both the healthy women and PCOS patients (p < 0.001), but silencing of INSR expression blocked the effects of insulin. Insulin induced significantly more apoptosis in GCs from PCOS patients than from healthy women (p < 0.01). Insulin significantly increased the ratio of p-Akt/Akt, the expression of mTOR protein, and the ratio of p-S6K1/S6K1 in GCs from normal control than in cells from PCOS patients (p < 0.001).
Conclusion: Insulin-induced apoptosis of GCs, less activation of Akt-mTOR signaling, and reduction of telomerase activity may be associated with the pathogenesis of PCOS.
Keywords: Akt; Apoptosis; Granulosa cells; Insulin; Insulin receptor gene; Polycystic ovary syndrome; mTOR.
© 2017 S. Karger AG, Basel.