Pueratin improves diminished ovarian reserve by inhibiting apoptosis

Pueratin (Pue) is an extract from Pueraria lobata, and exhibits therapeutic effects for the treatment of inflammation. However, the beneficial effects and mechanisms underlying Pue in the treatment of diminished ovarian reserve (DOR) remains to be fully elucidated. The aim of the present study was to investigate the effect of Pue on Bcl-2 and Bax protein expression in rats with DOR, associated with infertility within clinical practice, induced by 4-vinylcyclohexene diepoxide (VCD). A model of DOR was established in female Sprague Dawley rats by an intraperitoneal injection of 80 mg/kg VCD daily for 45 days. From day 1, the Sprague Dawley rats were orally administered with drugs daily for 45 days. They were divided into normal, model, Pue-low dose (L), Pue-medium dose (M) and Pue-high dose (H) groups (50, 100 and 300 mg/kg Pue, respectively). Follicle-stimulating hormone (FSH), luteinizing hormone (LH) and estradiol (E-2) levels were subsequently detected using ELISA. H&E staining and TUNEL staining were used to evaluate histopathological changes and apoptosis levels in the ovary, respectively. Bcl-2 and Bax protein expression levels in rat ovaries were evaluated using immunohistochemistry and western blotting. Compared with those in the model group, FSH and LH levels in the Pue-L, -M and -H groups were significantly decreased, whilst E-2 levels were significantly increased (P<0.05). After intragastric administration, the volume of the ovaries and uteri of rats in the Pue groups was increased compared with the model group, and the numbers of primordial follicles and primary follicles were also increased. The number of apoptotic cells and the expression of Bax were significantly reduced in a dose-dependent manner (P<0.05), compared with the model group. In addition, Bcl-2 protein expression and the Bcl-2/Bax ratio were found to be significantly increased in the Pue-treated groups in a dose-dependent manner (P<0.05), compared with the model group. In conclusion, Pue treatment improved ovarian function by regulating hormone balance in addition to Bcl-2 and Bax expression.