Effects of a ketogenic diet on reproductive and metabolic phenotypes in mice with polycystic ovary syndrome†

Polycystic ovary syndrome (PCOS) is one of the most common female reproductive and metabolic disorders. The ketogenic diet (KD) is a diet high in fat and low in carbohydrate. The beneficial effects of KD intervention have been demonstrated in obese women with PCOS. The underlying mechanisms, however, remain unknown. The aim of the present study was to investigate the effects of a KD on both reproductive and metabolic phenotypes of dehydroepiandrosterone (DHEA)-induced PCOS mice. Female C57BL/6 mice were divided into three groups, designated Control, DHEA, and DHEA+KD groups. Mice of both Control and DHEA groups were fed the control diet, whereas DHEA+KD mice were fed a KD with 89%(kcal) fat for 1 or 3 weeks after PCOS mouse model was completed. At the end of the experiment, both reproductive and metabolic characteristics were assessed. Our data show that KD treatment significantly increased blood ketone levels, reduced body weight and random and fasting blood glucose levels in DHEA+KD mice compared with DHEA mice. Glucose tolerance, however, was impaired in DHEA+KD mice. Ovarian functions were improved in some DHEAmice after KD feeding, especially in mice treated with KD for 3 weeks. In addition, inflammation and cell apoptosis were inhibited in the ovaries of DHEA+KD mice. Results from in vitro experiments showed that the main ketone body beta-hydroxybutyrate reduced inflammation and cell apoptosis in DHEA-treated KGN cells. These findings support the therapeutic effects of KD and reveal a possible mechanism by which KD improves ovarian functions in PCOS mice. Our findings support the role of KD intervention in weight loss, reducing blood glucose, and improving ovarian functions in PCOS mice and reveal a possible mechanism by which KD improved ovarian functions by inhibiting inflammation and cell apoptosis in ovarian granulosa cells in PCOS.