Vagus nerve stimulation (VNS) exerts
neuroprotective effects against
cerebral ischemia/reperfusion (I/R) injury and modulates redox status, potentially through the activity of miR-210, an important
microRNA that is regulated by
hypoxia-inducible factor and Akt-dependent pathways. The aim of this study was to determine the mechanisms of VNS- and miR-210-mediated hypoxic tolerance. Male Sprague-Dawley rats were preconditioned with a miR-210
antagomir (A) or with an
antagomir control (AC), followed by
middle cerebral artery occlusion and VNS treatment. The animals were divided into eight groups:
sham I/R, I/R, I/R+AC, I/R+A,
sham I/R+VNS, I/R+VNS, I/R+VNS+AC, and I/R+VNS+A. Activation of the endogenous
cholinergic a7
nicotinic acetylcholine receptor (a7nAchR) pathway was identified using double immunofluorescence staining. miR-210 expression was measured by PCR. Behavioral outcomes,
infarct volume, and neuronal apoptosis were observed at 24 h following reperfusion. Markers of oxidative stress were detected using ELISA. Rats treated with VNS showed increased miR-210 expression as well as decreased apoptosis and
antioxidant stress responses compared with the I/R group; these rats also showed increased p-Akt
protein expression and significantly decreased levels of cleaved
caspase 3 in the ischemic penumbra, as measured by western blot and immunofluorescence analyses, respectively. Strikingly, the beneficial effects of VNS were attenuated following miR-210 knockdown. In conclusion, our results indicate that miR-210 is a potential mediator of VNS-induced neuroprotection against I/R injury. Our study highlights the neuroprotective potential of VNS, which, to date, has been largely unexplored. Since approved by the FDA in 1997,
vagus nerve stimulation (VNS) has proven to be a safe and effective treatment for
refractory epilepsy and resistant depression. Recent studies have found that VNS also provided
neuroprotective effects against ischemic injury in a rat
stroke model. We showed that miR-210 played an important role in the
antioxidant stress and anti-apoptosis responses induced by VNS. This is the first report showing the effects of VNS at the
mRNA level. Therefore, VNS represents a promising candidate treatment for
ischemic stroke patients. Schematic view of the role of miR210 mediated in the protective effects of the VNS on the acute
cerebral ischemia. VNS acts to activate neuronal and astrocytes a7nAchR , inhibits the apoptosis and
oxidant stress responses possibly associated with increased Akt phosphorylation and miR210 expression.