Impacts of Metformin on Local Ovarian Cell Tissue of Rats with Polycystic Ovary Syndrome and Intestinal Flora Under Aerobic Exercise

Abstract

In order to explore the possible treatment mechanism of metformin on the local ovarian cell tissue of rats with polycystic ovary syndrome (PCOS), 35 female clean sterile rats were selected as the research objects in this study, and randomly divided a PCOS model group (PCOS MG) (25 rats) and a control group (CG) (10 rats). After the modelling was completed, 5 rats were randomly selected to evaluate the modelling effect. When the success rate was higher than 80%, the remaining model rats were divided into two groups randomly, namely the (PCOS MG) (10 rats) and the treatment group (TG) (10 rats). Hematoxylin-eosin (HE) staining was performed on ovarian tissue of the rat, and the ovarian tissue structure was observed under light microscope. Immunohistochemistry was used to detect the distribution and expression levels of tumour necrosis factor-α (TNF-α), insulin-like growth factor-I (IGF-I), and connective tissue growth factor (CTGF) on the ovaries of rats in each group. It was found by observing the vaginal smear under the microscope that the rats in the (PCOS MG) had lost the regular estrous cycle, suggesting that there was no ovulation. The expression levels of TNF-α and CTGF in rats in the (PCOS MG) were greatly higher than those in the CG (P < 0.05); compared with the (PCOS MG), the expression levels of TNF-α and CTGF in the TG were decreased observably (P < 0.05). IGF-I was mainly expressed in granulosa cells (GCs) and follicular membrane cells (FMCs) of the ovarian tissue. The expression level of IGF-I in ovarian GCs in rats in the (PCOS MG) was significantly higher than that in the CG (P < 0.05). The expression level of IGF-I in GCs in the TG was lower significantly than that in the (PCOS MG) (P < 0.05). By comparing with rats in the CG, the rats in the (PCOS MG) had obviously decreased Actinobacteria and Betaproteobacteria in the intestinal tract, and the proportion of Firmicutes in the intestine was significantly increased; the amount of butyric acid in the faeces of rats with aerobic exercise was obviously higher than that in the (PCOS MG), because exercise increased the proportion of intestinal butyric acid-producing bacteria. Conclusion: metformin combined with aerobic exercise can treat the PCOS by regulating serum hormone levels and the expression levels of TNF-α, IGF-I, and CTGF.