TIGAR relieves PCOS by inhibiting granulosa cell apoptosis and oxidative stress through activating Nrf2

Abstract

This study aimed to elucidate the role of TP53-induced glycolysis and apoptosis regulator (TIGAR) in polycystic ovary syndrome (PCOS). A rat model PCOS was constructed by subcutaneous injection with dehydroepiandrosterone (DHEA). Follicular atresia and reduced granular cells (GCs) in ovaries suggested successful modeling. The low expression of TIGAR was observed in ovarian tissue of PCOS rat. To explore the role of TIGAR in PCOS, lentivirus carrying the TIGAR were used to up-regulate TIGAR expression. TIGAR overexpression reduced the DHEA-induced increase of ovarian weight, the levels of estradiol (E2), and the ratio of luteinizing hormone/follicle-stimulating hormone (LH/FSH) in the serum, as well as improved the morphology of the follicle, especially increased the thickness of the GC layer, which attributed to the inhibition of apoptosis by TIGAR. In addition, high expression of TIGAR inhibited oxidative stress in ovaries of PCOS rat, as evidenced by decreased level of malondialdehyde (MDA), and reactive oxygen species (ROS), and enhanced activity of glutathione peroxidase (GPX) and superoxide dismutase (SOD). Mechanically, Nrf2/OH-1 signal pathway was activated by TIGAR. The effect of TIGAR on PCOS were verified in the primary rat GCs treated with dihydrotestosterone, but also the rescue experiment was performed. Downregulation of Nrf2 reversed the effects of TIGAR, indicating that TIGAR suppressed oxidative stress and GC apoptosis by activating Nrf2/OH-1 pathway in PCOS. Finally, non-targeted metabolomics revealed that TIGAR might affect the energy metabolic pathway, thereby altering the metabolic profile of primary rat GCs. This study provided new insights into the prevention and treatment of PCOS.