[Effect of Yes-associated protein in regulation of electroacupuncture pretreatment on cerebral ischemia reperfusion injury rats]

Abstract

Objective: To observe the effect of electroacupuncture (EA) pretreatment on inflammatory reaction, apoptosis and expression of Yes-associated protein (YAP) of ischemic penumbra of cerebral cortex in cerebral ischemia reperfusion injury rats, and to explore the possible mechanism of its neuroprotection effect.

Methods: A total of 84 SD rats were randomized into a sham operation group (12 rats), a model group (18 rats), an EA group (18 rats), an EA+YAP virus transfection group (18 rats) and an EA+virus control group (18 rats). Except for the sham operation group, thread embolization method was adopted to establish the middle cerebral artery occlusion (MCAO) model in rats of the other groups. EA was applied at "Baihui" (GV 20) and "Dazhui" (GV 14) for 30 min in the 3 EA intervention groups 2 h before model establishment, disperse-dense wave, 2 Hz/15 Hz in frequency and 1 mA in intensity. Adenovirus transfection technique was used to induce gene silencing of YAP in the EA+YAP virus transfection group, and adenovirus vectors was injected as negative control in the EA+virus control group 4 d before model establishment. Twenty-four hours after model establishment, neurological function score was evaluated, the relative cerebral infarction area was observed by TTC staining, the apoptosis in the ischemic penumbra of cerebral cortex was detected by TUNEL staining, the levels of inflammatory factors IL-1β, IL-6 and TNF-α in the ischemic penumbra of cerebral cortex was detected by ELISA method, the expression of YAP was detected by Western blot and immunofluorescence.

Results: Compared with the sham operation group, the expression of YAP was increased in the model group (P<0.05); compared with the model group, the expression of YAP in the ischemic penumbra of cerebral cortex was increased in the EA group (P<0.05). Compared with the sham operation group, the neurological function score, the percentage of TUNEL positive cells and the levels of IL-1β, IL-6 and TNF-α in the ischemic penumbra of cerebral cortex were increased in the model group (P<0.001, P<0.01); compared with the model group, the neurological function score, the relative cerebral infarction area, the percentage of TUNEL positive cells and the levels of IL-1β, IL-6 and TNF-α in the ischemic penumbra of cerebral cortex were decreased in the EA group (P<0.05, P<0.01); compared with the EA group, the neurological function score, the relative cerebral infarction area, the percentage of TUNEL positive cells and the levels of IL-1β, IL-6 and TNF-α in the ischemic penumbra of cerebral cortex were increased in the EA+YAP virus transfection group (P<0.01, P<0.05); compared with the EA+YAP virus transfection group, the neurological function score, the relative cerebral infarction area, the percentage of TUNEL positive cells and the levels of IL-1β, IL-6 and TNF-α in the ischemic penumbra of cerebral cortex were decreased in the EA+virus control group (P<0.01, P<0.05).

Conclusion: Electroacupuncture pretreatment can effectively improve the ischemia reperfusion injury, its mechanism may be related to up-regulating the expression of YAP in the ischemic penumbra of cerebral cortex and relieving the apoptosis and inflammatory reaction.

Keywords: Yes-associated protein (YAP); apoptosis; electroacupuncture; inflammatory reaction; ischemia reperfusion injury; ischemia stroke; pretreatment; stroke.