Differences of manifestation and gut microbiota composition between different polycystic ovary syndrome rat models

Objective To explore a more appropriate animal modeling method of polycystic ovary syndrome (PCOS) model, and clarify the variance and mechanism of gut microbiota in PCOS models. Methods Totally 30 female Sprague Dawley rats were involved in this study. They were randomly divided into control group, dehydroepiandrosterone (DHEA) group and DHEA+light group, respectively, with 10 rats in each group. Subcutaneous injection of 0.2 mL DHEA was adopted to establish PCOS rat models and 0.2 mL PBS was injected in control group rats. Rats of control group and DHEA group were under 12 h/12 h light/dark exposure. Rats of DHEA+light group were injected with equivalent volume of DHEA and under 24 h continuous light exposure. After treatment for 4 weeks, the estrous cycle, ovarian weight, morphological changes and fasting blood glucose were detected. Gut microbiota of rats was explored with 16S rRNA sequencing technique. Results After treatment for 4 weeks, rats in DHEA group had disordered estrous cycles, reduced ovarian weight and polycystic ovaries. Apart from PCOS-like manifestations in DHEA, rats of DHEA+light group had increased fasting blood glucose level (P<0.001). The composition of gut microbiota was different between DHEA group and DHEA+light group. In genus level, Straphylococcus, Jeotgalicoccus and Lachnospiracea incertae sedis were enriched in DHEA+light group while the abundance of Alloprevotella and Phascolarctobacterium were decreased compared with DHEA group. Prediction function analysis implied that there might be association between altered microbial taxa and glucose metabolic pathway in PCOS. Conclusion DHEA injection with continuous light exposure induced reproductive and metabolic changes in rats, which were closely similar with the manifestation of PCOS patients. It is a more suitable method to induce PCOS animal model. It is possible that gut microbiota might play a role in the process of glucose metabolic impairment induced by continuous light. Key words: Polycystic ovary syndrome; Models, animal; Dehydroepiandrosterone; Continuous light; Gut microbiota