Beneficial effects of apigenin on ovarian histological changes and angiogenesis gene expression in rat model of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common heterogeneous reproductive disorder and can affect approximately 10% of women of reproductive age. Abnormal vasculogenesis is a common event in polycystic ovary syndrome. This study planned to evaluate the antiangiogenic role of apigenin in ovarian histology, gene expression, and vascular density and stability in an experimental model of PCOS. Twenty-eight rats weighing 180-250 g were divided into 4 groups. Seven rats in the control group remain intact and without treatment. In 21 rats, an ovary polycystic model with a single injection of estradiol valerate was established. The PCOS rats were treated with vehicle, apigenin 10, or apigenin 20 mg/kg in three different PCOS groups for 14 days. At the end, a histological assessment of the ovaries was performed to determine collagen density and follicle counting. The endothelial or periendothelial cells were determined by immunohistochemical assay, and angiogenesis gene expression was determined using molecular assessments. Apigenin treatment partially restored follicular development, decreased the number of cysts, and increased corpora lutea in PCOS rats. Also, apigenin decreased the collagen density in the polycystic ovaries. However, apigenin administration mitigated ovarian angiogenesis by a reduction in endothelial and periendothelial cell numbers. A decrease in VEGF and VEGF R2 (kinase insert domain receptor, KDR) expressions was found after the treatment of rats with apigenin. Conclusively, our data revealed that apigenin improves ovarian histological alterations and follicular dynamics in polycystic ovary rats. The effect is partially mediated by suppression of the VEGF signaling system and reduction in endothelial and periendothelial cell proliferation.