β-hydroxybutyrate alleviates neurological deficits by restoring glymphatic and inflammation after subarachnoid hemorrhage in mice.

Both glymphatic system dysfunction and inflammatory response aggravate neurological dysfunction after subarachnoid hemorrhage (SAH). Studies have shown that β-hydroxybutyrate (BHB) may mitigate painful diabetic neuropathy (PDN) by upregulating SNTA1 expression and reinstating AQP4 polarity. However, the potential of BHB to ameliorate glymphatic system function and inflammatory response in SAH mice remains uncertain. The SAH models were constructed by injection of arterial blood into cisterna Magana. Three groups of C57 mice were randomly assigned: Sham, SAH, and BHB. All mice were subjected to neurological function assessment, western blot, immunofluorescence double staining, and RNA-seq. Glymphatic system function was examined with tracer and immunofluorescence double staining, and the differential genes were examined with RNA-seq. In addition, the expression of related inflammation was detected. Compared with the SAH group, BHB reinstated AQP4 polarization by upregulating SNTA1 protein to enhance the glymphatic system. According to RNA-seq, the different genes were primarily connected to microglia activation, astrocytes, and inflammation. Western blot and immunofluorescence further confirmed that the related inflammatory protein expression levels were upregulated. BHB attenuated neuroinflammation after SAH. Ultimately, it can mitigate the neurological deficits in SAH mice. The study reveals a novel mechanism that BHB treatment mitigates neurologic impairment in SAH mice. We propose that BHB may play a neuroprotective effect by enhancing glymphatic system function and attenuating neuroinflammatory subarachnoid hemorrhage. After subarachnoid hemorrhage(SAH), the polarity of AQP4 decreases and the function of the glymphatic system is impaired, leading to metabolic waste deposition such as Aβ and the accumulation of inflammatory factors. At the same time, astrocyte and microglia activation, and secretion of inflammatory cytokines, such as TNF-α, and IL-1β, aggravate neurological dysfunction. BHB improves neurological dysfunction by improving the glymphatic system and astrocyte and microglial inflammation. [Display omitted] • The downregulation of SNTA1 resulted in the depolarization of AQP4, contributing to impaired glymphatic system function following SAH. • Treatment with β-hydroxybutyrate (BHB) reinstated AQP4 polarization through upregulation of SNTA1 expression, thereby enhancing glymphatic system function in SAH mice. • BHB treatment attenuated the neuroinflammatory response in SAH mice. • BHB treatment mitigated neurological deficits in SAH mice. [ABSTRACT FROM AUTHOR]