Study on alleviating neuroinflammatory injury in ischemic stroke rats by electrical stimulation with scalp acupuncture based on IFN-γ mediated JAK/STAT1 signaling pathway

Abstract

To explore the molecular mechanism of electrical stimulation with scalp acupuncture (ESA) in alleviating neuroinflammatory injury in ischemic stroke rats based on interferon γ (IFN-γ)-mediated Janus kinase/signal transduction and transcriptional activator 1 (JAK/STAT1) signaling pathway. Fifty-six SD rats aged 7 weeks were randomly divided into normal, model, ESA and inhibitor groups, with 14 rats in each group. The middle cerebral artery embolization rat model was established by means of thread embolization. Rats in the inhibitor group were intraperitoneally injected with the inhibitor PJ34 (5 mg/mL, 25 mg/kg) once a day for 7 days. Rats in the ESA group were treated at bilateral anterior parietotemporal slash (MS6) with ESA (2 Hz/100 Hz, 1 mA), 30 min a day for 7 days. Before and after interventions, the neurological deficit score and neurobehavioral score were evaluated. The percentage of cerebral infarction volume was detected by TTC staining. The positive expressions of interleukin (IL)-6 and IL-10 in cerebral cortex were detected by immunohistochemistry. The protein expression levels of IFN-γ, JAK1, JAK2 and phosphorylated (p)-STAT1 in rats cerebral cortex were detected by Western blot. Compared with the normal group, the neurological deficit score, neurobehavioral score, the percentage of cerebral infarction volume, the expression levels of IL-6, IFN-γ, JAK1, JAK2 and p-STAT1 in cerebral cortex were increased (P<0.01), while the expression level of IL-10 was decreased (P<0.01) in the model group. Compared with the model group, the neurological deficit score and neurobehavioral score after treatment were significantly decreased (P<0.01), the percentage of cerebral infarction volume was decreased (P<0.01), the expression levels of IL-6, IFN-γ, JAK1, JAK2 and p-STAT1 in cerebral cortex were decreased (P<0.01), while the expression level of IL-10 was increased (P<0.01) in the ESA and inhibitor groups. ESA was superior to inhibitors in improving neurological deficit score and down-regulating p-STAT1 expression (P<0.05, P<0.01), and was inferior to inhibitor in reducing the percentage of cerebral infarction volume as well as down-regulating IFN-γ and JAK1 (P<0.01, P<0.05). Down-regulating the expression of IFN-γ and inhibiting the activity of JAK/STAT1 signaling pathway may be one of the mechanisms by which ESA alleviates neuroinflammatory injury in ischemic stroke rats.