Bezafibrate Restores the Inhibition of FSH-Induced Follicular Development and Steroidogenesis by Tumor Necrosis Factor-Alpha Through Peroxisome Proliferator-Activated Receptor-Gamma Pathway in an In Vitro Mouse Preantral Follicle Culture1

Abstract

We recently reported that bezafibrate, a lipid-lowering drug of the fibrate class, administered in addition to clomiphene citrate (CC) successfully induced ovulation in CC-resistant polycystic ovary syndrome (PCOS) patients. We hypothesized that bezafibrate may directly affect ovarian follicle development. Insulin resistance and compensatory hyperinsulinemia are important for the pathogenesis of PCOS. In this study, we first examined the effects of tumor necrosis factor-alpha (TNF), which plays a role in insulin resistance, on follicle development by using the follicle culture system. TNF significantly inhibited follicle-stimulating hormone (FSH)-induced follicle development, 17beta-estradiol (E2) secretion, and ovulation rate in a dose-dependent manner. We then examined whether bezafibrate treatment could rescue the inhibition of FSH-induced follicle development and steroidogenesis by TNF. Bezafibrate treatment rescued inhibition of follicle development, secretion of E2, and ovulation rate by TNF. We examined the expression of peroxisome proliferator-activated receptor (PPAR) subtypes in mouse preantral follicles. As the protein expression of only PPARG was observed in mouse preantral follicles, we examined whether bezafibrate could affect follicle development and steroidogenesis through PPARG pathways. Treatment with GW1929, a selective PPARG agonist, restored inhibition of FSH-induced follicle development and steroidogenesis by TNF, whereas treatment with GW9662, a selective PPARG antagonist, canceled the restorative effects of bezafibrate. Collectively, the results in this study suggest that bezafibrate may directly exhibit a restorative effect on the inhibition of ovarian follicle development and steroidogenesis by TNF through the PPARG pathway.