The sperm quality in DIO male mice is linked to the NF-κB signaling and Ppp2ca expression in the hypothalamus. The sperm quality in DIO male mice is linked to the NF-κB signaling and Ppp2ca expression in the hypothalamus

Emerging studies have reported a significant correlation between obesity and a decline in sperm quality among males, however, the underlying mechanism remains elusive. In this study, we observed that male mice with diet-induced obesity (DIO) exhibited functional alteration in the hypothalamic-pituitary-gonadal (HPG) axis, as evidenced by disruption of luteinizing hormone (LH) pulse release. This alteration was attributed to the activation of nuclear factor kappa B subunit (NF-κB) signaling in the hypothalamus, which subsequently led to a decline in sperm quality. The application of RNA-seq analysis in the hypothalamic arcuate nucleus (ARC) of DIO male mice has revealed a signaling network implicating protein phosphatase 2 catalytic subunit alpha (Ppp2ca), which is involved in the disruption of LH pulse secretion. Activation of NF-κB signaling increased expression, which decreased the Kiss1 expression through inhibition of Akt kinase (AKT) and cAMP responsive element binding protein 1 (CREB1) activities. Overexpression of the Ppp2ca gene in the hypothalamic ARC resulted in disrupted LH pulse secretion patterns and reduced sperm quality. Collectively, our findings provide novel insights into the molecular mechanisms underlying the decline in sperm quality observed in male DIO mice. Overall design: Four weeks old male mice were fed either an ordinary diet (NCD; 16.5% fat, cobio, catalog No:1010086) or a high-fat diet (HFD; 60% fat, Research Diets, catalog No: D12492) for 16 weeks. Mouse body weight was measured every week.The brains of mice were harvested and thoroughly washed in cold PBS solution until complete removal of any residual blood on their surfaces was achieved. Subsequently, they were preserved by embedding them in OCT compound and storing them at -80℃. Brain tissue sections measuring 20 μm thickness were obtained using a Microtome Cryostat (Thermo, America). These sections were securely mounted onto slides coated with laser microcut membrane (Leica, 11505190). A laser microdissection system (Leica, Germany) was employed to precise excision ARC regions within the brain sections. The harvest tissues were collected into a RNase-free tube and storage at -80℃.