Electroacupuncture promotes myelin repair in the corpus callosum region of cerebral ischemic rats by modulating microglia activation and polarization

BACKGROUND: Ischemic stroke can damage the cerebral white matter, resulting in myelin loss and neurological deficits. Moreover, microglial activation plays an important role in ischemic stroke; therefore, inhibiting microglial activation has become an effective therapeutic target for ischemic stroke. OBJECTIVE: This study aimed to investigate the effects of electroacupuncture (EA) on microglial activation and polarization, and the role of oligodendrocyte genesis in myelin reformation after ischemic stroke. METHODS: A rat model of permanent middle cerebral artery occlusion (p-MCAO) was established and treated with EA. The reparative effect of EA on corpus callosum (CC) injury in p-MCAO rats was evaluated using a nesting assay, Luxol fast blue staining, immunofluorescence staining, and Western blot. Additionally, quantitative real-time polymerase chain reaction was employed to measure inflammatory factors IL-1β and IL-10 expression levels. RESULTS: The results showed that p-MCAO rats exhibited significantly impaired nesting ability, severe myelin loss in the CC region, reduced Olig2 protein expression, activated microglia, and predominately M1-type microglial polarization. EA treatment improved nesting behavior, mitigated myelin loss, enhanced Olig2 expression, suppressed excessive microglial activation, downregulated IL-1β, and upregulated IL-10 expression levels. CONCLUSIONS: These findings indicate that EA facilitates myelin repair in ischemic cerebral white matter by suppressing M1 microglial polarization, inducing an M2 phenotypic shift, modulating inflammatory responses, and enhancing oligodendrocyte regeneration.