[Modified Dihuang Decoction improves ovarian reserve in mice by regulating Bcl-2-related mitochondrial apoptosis pathway]

Abstract

The present study investigated the effect of Modified Dihuang Decoction in improving ovarian reserve in mice through the Bcl-2-related mitochondrial apoptosis pathway. Forty-eight adult female BALB/c mice were randomly divided into the following six groups with eight mice in each group: a blank group, a model group, a femoston group(three cycles of treatment with 0.13 mg·kg~(-1) estradiol tablets for 2 days and 1.43 mg·kg~(-1) estradiol and dydrogesterone tablets for 3 days), and high(64.74 g·kg~(-1))-, medium(43.16 g·kg~(-1))-, and low-dose(21.58 g·kg~(-1)) Modified Dihuang Decoction groups. Mice in other groups except the blank group received a single intraperitoneal injection of 12 mg·kg~(-1) cyclophosphamide and 1.2 mg·kg~(-1) busulfan to induce a model of diminished ovarian reserve(DOR), while those in the blank group received an equal volume of normal saline. Mice were treated with corresponding drugs for 15 d from the 36 th day, once per day, and the mice in the blank group and the model group were treated with an equal volume of normal saline. The general condition and oestrous cycle were observed. The serum hormone levels were detected with the enzyme-linked immunosorbent assay(ELISA). The morphological changes of ovaries were observed by HE staining. Western blot was used to detect the protein expression of cysteinyl aspartate specific proteinase-9(caspase-9), cleaved caspase-3, Bcl-2 associated X protein(Bax), Bcl-2, superoxide dismutase-2(SOD-2), and glutathione peroxidase-1(GPx-1). The mRNA expression of Bax and Bcl-2 was detected by real-time fluorescence-based quantitative polymerase chain reaction(real-time PCR). The results showed that compared with the blank group, the model group showed body weight loss, disordered oestrous cycle, elevated serum levels of follicle-stimulating hormone(FSH) and luteinizing hormone(LH), reduced serum levels of estradiol(E_2), anti-mullerian hormone(AMH), and inhibin B(INHB), the declining number of ovarian follicles and granulosa layers, increased number of atretic follicles, up-regulated protein expression of caspase-9, cleaved caspase-3, and Bax and Bax mRNA expression in ovaries, and down-regulated protein expression of Bcl-2, SOD-2 and GPx-1, and Bcl-2 mRNA expression. Compared with the model group, the Modified Dihuang Decoction groups displayed restored body weight and oestrous cycle, decreased serum levels of FSH and LH, elevated serum levels of E_2, AMH, and INHB, increased number of ovarian follicles, thickened granulosa layers, and declining number of atretic follicles. Additionally, the protein expression of caspase-9, cleaved caspase-3, and Bax, and Bax mRNA expression was down-regulated, and the protein expression of Bcl-2, SOD-2, and GPx-1, and Bcl-2 mRNA expression was up-regulated. The results suggest that Modified Dihuang Decoction can regulate endocrine hormone, promote follicle growth and improve ovarian reserve by enhancing ovarian anti-oxidant capacity, inhibiting the Bcl-2-related mitochondrial apoptosis pathway, and further inhibiting cell apoptosis.

Keywords: Bax; Bcl-2; Modified Dihuang Decoction; apoptosis; diminished ovarian reserve; oxidative stress.