β-hydroxybutyrate regulates microglia M1/M2 polarization and phagocytosis through the JAK1/STAT1 pathway to reduce neuroinflammation and exert anti-epileptic effects.

Neuroinflammation and microglia M1/M2 polarization imbalance are among the core pathological mechanisms of epilepsy (EP), with the JAK1/STAT1 pathway being vital in neuroinflammation. β-hydroxybutyrate (BHB), a ketone body metabolite, has anti-inflammatory and neuroprotective potential, but whether it can ameliorate EP-related neurological damage by modulating this pathway remains unclear. To investigate whether BHB regulates microglia polarization and phagocytosis through the JAK1/STAT1 pathway, attenuates neuroinflammation and neuronal injury, and thus exerts anti-EP effects. A rat primary neuronal EP model and lipopolysaccharide (LPS)-induced M1-type microglia model were constructed, and microglia polarization, migration, phagocytosis, and neuronal damage were detected by scratch assay, flow cytometry, Hoechst 33,342/PI staining, Cell Counting Kit-8 assay, and ELISA kits. A rat model of Pentetrazol (PTZ)-induced EP was constructed to detect the effects of BHB on the symptoms of EP in rats by behavioral assessment, and to detect brain tissue damage by pathological staining. Western blot was conducted to detect microglia polarization markers, neuronal apoptosis, synapse-related proteins, and JAK1/STAT1 pathway-related proteins expression. Pathway specificity was verified using JAK1 overexpression plasmid (OE-JAK1) and STAT1 inhibitor (Fludarabine). BHB concentration-dependently increased EP neuron viability and suppressed M1 polarization induced by LPS, and promoted M2 polarization. BHB also enhanced the migration and phagocytosis of microglia, and reduced pro-inflammatory factor release, which in turn attenuated their pro-inflammatory damage to neurons and protected synaptic integrity, and this effect was linked to its suppression of JAK1/STAT1 pathway activation. Additionally, BHB extended seizure latency, decreased seizure duration, and reduced seizure severity in EP rats, and effectively attenuated brain histopathological damage and promoted neuronal regeneration and axonal repair. Furthermore, BHB was also effective in promoting microglia M2 polarization and enhancing their phagocytosis in vivo. Overexpression of JAK1 attenuated the neuroprotective effects of BHB, and Fludarabine attenuated the impacts of overexpression of JAK1. By inhibiting the JAK1/STAT1 pathway, BHB promotes microglia M2 polarization and enhances their phagocytosis, attenuates neuroinflammation and neuronal injury, and ultimately exerts anti-EP effects.