Dapagliflozin Ameliorates Ovulation Disorders via Attenuating Activated Microglia-Mediated Hypothalamic Inflammation in HFD-Fed Mice

Abstract

Introduction: Sodium-glucose cotransporter 2 inhibitors (SGLT2is) have shown neuroprotective effects in obese mice. However, whether SGLT2i can ameliorate high-fat diet (HFD)-related ovulation disorders remains unknown. The aim of this research was to investigate whether dapagliflozin improves HFD-induced ovulatory dysfunction by attenuating microglia-mediated hypothalamic inflammation. Methods: C57BL/6J female mice fed HFD were treated with dapagliflozin (1 mg/kg) for 22 weeks. Plasma insulin, leptin, luteinizing hormone (LH), estradiol (E2), and IL-1β levels were also tested. Microglial morphology, cell numbers, and SGLT2 expression were evaluated using immunofluorescence. The expression of IL-1β, NLRP3, kisspeptin, gonadotropin-releasing hormone (GnRH), SGLT2, insulin, and leptin receptors in the hypothalamus was determined using immunohistochemical staining. We also examined the effects of dapagliflozin on glucose metabolism and the release of inflammatory factor in palmitic acid (PA)-treated HMC3 cells. Results: As expected, dapagliflozin improved HFD-induced metabolic disturbances, peripheral versus central insulin and leptin resistance and also restored the regular estrous cycle. Furthermore, dapagliflozin blunted microglia activation, NLRP3 inflammasome priming, hypothalamic inflammation, and increased the expression of GnRH and kisspeptin at proestrus in the hypothalamus. Additionally, dapagliflozin markedly reduced IL-6 and NO release and fat accumulation, decreased lactic acid production and glucose consumption, and inhibited mammalian target of rapamycin (mTOR) and hexokinase 2 (HK2) expression in PA-treated HMC3 cells. These effects suggest that dapagliflozin reduced the mTOR/HK2-mediated aerobic glycolysis. Conclusions: Dapagliflozin improved HFD-related ovulation disorders by regulating glucose metabolism through mTOR/HK2 signaling and attenuating microglia-mediated hypothalamic inflammation. These results validate the novel role for the neuroprotection of SGLT2i in HFD-induced obesity and ovulation disorders.