Impairment of oocyte quality caused by gut microbiota dysbiosis in obesity.

Obesity poses risks to oocyte maturation and embryonic development in mice and humans, linked to gut microbiota dysbiosis and altered host metabolomes. However, it is unclear whether symbiotic gut microbes have a pivotal role in oocyte quality. In mouse models of fecal microbiota transplantation, we demonstrated aberrant meiotic apparatus and impaired maternal mRNA in oocytes, which is coincident with the poor developmental competence of embryos. Using metabolomics profiling, we discovered that the cytosine and cytidine metabolism was disturbed, which could account for the fertility defects observed in the high-fat diet (HFD) recipient mice. Additionally, cytosine and cytidine are closely related with gut microbiota dysbiosis, which is accompanied by a notable reduction of abundance of Christensenellaceae R-7 group in the HFD mice. In summary, our findings provided evidence that modifying the gut microbiota may be of value in the treatment of infertile female individuals with obesity.