Kisspeptin regulates the proliferation and apoptosis of ovary granulosa cells in polycystic ovary syndrome by modulating the PI3K/AKT/ERK signalling pathway

BACKGROUND: The development of polycystic ovary syndrome (PCOS) is closely correlated with apoptosis and oxidative stress in ovarian granulosa cells. Kisspeptin plays an important role in reproductive organ function. This study aimed to explore the role of kisspeptin in PCOS and oxidative stress-triggered apoptosis of ovarian granular cells. METHODS: A PCOS rat model was established by injecting dehydroepiandrosterone (DHEA) and feeding the rats a high-fat diet. The RNA and protein levels of kisspeptin were analysed by quantitative PCR, western blotting, and histological staining. Tissue damage was evaluated using haematoxylin and eosin (H&E) staining. The viability and proliferation of human granulosa cell KGN were measured using the cell counting kit-8 (CCK-8) and 5-ethynyl-2′-deoxyuridine (EdU) assays. Cell cycle and apoptosis were analysed by flow cytometry. Oxidative stress was analysed by measuring reactive oxygen species (ROS), malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) levels. RESULTS: Kisspeptin was downregulated in the ovarian granulosa cells of PCOS rats compared to those of control rats. Kisspeptin overexpression enhanced KGN cell proliferation and inhibited apoptosis. ROS generation was suppressed by kisspeptin, along with decreased levels of MDA and increased levels of the antioxidants GSH, SOD, and CAT. Kisspeptin activates PI3K/AKT and ERK signalling, and inactivation of ERK1/2 suppresses the protective role of kisspeptin in ovarian granulosa cells. CONCLUSION: Kisspeptin improves proliferation and alleviates apoptosis and oxidative stress in ovarian granulosa cells by activating PI3K/AKT and ERK signalling.