关键词: 脑缺血再灌注损伤, 电针, NLRP3, 活性氧, 硫氧还蛋白互作蛋白, 小胶质细胞

Abstract: BACKGROUND: Previous studies have demonstrated that acupuncture at the governor meridian has precise efficacy in the treatment of ischemic stroke and can improve cerebral ischemia-reperfusion injury by attenuating pyroptosis, but the upstream regulatory mechanisms are not yet fully clarified.
OBJECTIVE: To observe the neuroprotective effect of electroacupuncture in model rats of cerebral ischemia-reperfusion injury.
METHODS: Twenty-seven Sprague-Dawley rats were randomly divided into sham surgery, model, and electroacupuncture groups, with nine rats in each group. Modified suture method was used to establish cerebral ischemia-reperfusion model rats in the model and electroacupuncture groups. The electroacupuncture group was subjected to electroacupuncture at “Baihui,” “Fengfu,” and “Dazhui” acupoints, 20 minutes each, once a day, for 7 consecutive days. After treatment, neurological deficit scoring and pole test were performed to assess behavioral changes. Tri-phenyl tetrazolium chloride staining was used to assess cerebral infarction size in rats. Hematoxylin-eosin staining was performed to observe morphological changes in cerebral cortex tissue on the infarcted side of rats. Immunofluorescence analysis was used to determine Iba-1 and reactive oxygen species levels in cerebral cortex tissue on the infarcted side of rats, ELISA method was used for measuring interleukin-1β, interleukin-6 and tumor necrosis factor α levels in cerebral cortex tissue on the infarcted side of rats. Real-time fluorescence quantitative PCR and western blot were used to detect mRNA and protein expression levels of thioredoxin interaction protein, nod-like receptor associated protein 3 (NLRP3), Caspase-1 and interleukin-1β in cerebral cortex tissue on the infarcted side of rats respectively, and the interaction between thioredoxin interaction protein and NLRP3 was analyzed by immunoprecipitation. 
RESULTS AND CONCLUSION: (1) Compared with the sham surgery group, rats in the model group showed an increase in neurological deficit score, pole test score, cerebral infarction volume (P < 0.05), the immunofluorescence expression of Iba-1 and reactive oxygen species (P < 0.05), the levels of interleukin-1β, interleukin-6 and tumor necrosis factor α (P < 0.05), and the mRNA and protein expression of thioredoxin interaction protein, NLRP3, Caspase-1 and interleukin-1β in cerebral cortex tissue (P < 0.05). Hematoxylin-eosin staining in the model group showed neuronal degeneration and necrosis, with fragmented and dissolved nuclei and cellular vacuoles. (2) Compared with the model group, rats in the electroacupuncture group showed a reduction in neurological deficit score, pole climbing test score, cerebral infarction volume (P < 0.05), the immunofluorescence expression of Iba-1 and reactive oxygen species (P < 0.05), the levels of interleukin-1β, interleukin-6 and tumor necrosis factor α (P < 0.05), and the mRNA and protein expression of thioredoxin interaction protein, NLRP3, Caspase-1 and interleukin-1β in cerebral cortex tissue (P < 0.05). Hematoxylin-eosin staining showed that the pathological damage of neurons in cerebral cortex tissue on the infarcted side of rats in the electroacupuncture group was significantly attenuated, with significantly reduced cell necrosis and vacuolation. (3) Immunoprecipitation assay showed an interaction between thioredoxin interaction proteins and NLRP3 in the cerebral cortical tissues on the infarcted side of rats in the model group. To conclude, electroacupuncture has a significant therapeutic effect against cerebral ischemia-reperfusion injury, possibly by inhibiting the reactive oxygen species/thioredoxin interaction protein/NLRP3 cell pyroptosis signaling pathway and activation of microglia to reduce the release of inflammatory factors.

Key words: cerebral ischemia-reperfusion injury, electroacupuncture, NLRP3, reactive oxygen species, thioredoxin interaction protein, microglia