Vagus nerve stimulation is a potential treatment for ischemic stroke

Area of Science:

• Neuroscience
• Immunology
• Stroke Research

Background:

• Microglia, the brain's immune cells, adopt pro-inflammatory or regulatory phenotypes post-ischemic stroke.
• Vagus nerve stimulation (VNS) demonstrates neuroprotective potential in ischemia/reperfusion injury by modulating microglial phenotypes.

Purpose of the Study:

• To investigate the mechanism by which VNS influences microglial polarization in ischemic stroke.
• To determine the role of the α7 nicotinic acetylcholine receptor (α7nAChR) in VNS-mediated neuroprotection.

Main Methods:

• Rat models of ischemic stroke induced by middle cerebral artery occlusion.
• Vagus nerve stimulation applied 30 minutes post-stroke induction.
• Analysis of microglial phenotypes and inflammatory markers (iNOS, TNF-α, Arginase 1, TGF-β).
• Assessment of the Toll-like receptor 4 (TLR4)/nuclear factor kappa-B (NF-κB) pathway and α7nAChR blockade.

Main Results:

• VNS induced a shift from pro-inflammatory to regulatory microglial phenotypes in the ischemic penumbra.
• VNS decreased pro-inflammatory markers (iNOS, TNF-α) and increased regulatory markers (Arginase 1, TGF-β).
• VNS activated α7nAChR, which inhibited the TLR4/NF-κB pathway, crucial for VNS's neuroprotective effects.

Conclusions:

• Vagus nerve stimulation effectively regulates microglial polarization towards a neuroprotective phenotype after ischemic stroke.
• The α7 nicotinic acetylcholine receptor is a key mediator of VNS's therapeutic effects by inhibiting the TLR4/NF-κB pathway.
• VNS represents a promising therapeutic strategy for ischemic stroke, acting through neuro-immune modulation.