电针预处理对大鼠脑缺血再灌注时脑组织动力相关蛋白1活性的影响

Effects of electroacupuncture preconditioning on activity of dynamin-related protein 1 in brain tissues during cerebral ischemia-reperfusion in rats

目的评价电针预处理对大鼠脑缺血再灌注时脑组织动力相关蛋白1（Drp1）活性的影响。方法清洁级健康成年雄性Wistar大鼠126只，体重250～300 g，采用随机数字法分为3组（n＝42）：假手术组（S组）、缺血再灌注组（I/R组）和电针预处理组（EA组）。S组仅分离血管，不进行阻闭；I/R组采用线栓法阻断左侧大脑中动脉2 h后再灌注法制备局灶性脑缺血再灌注损伤模型；EA组电针刺激百会（2/15 Hz疏密波，强度1 mA），连续5 d，每次30 min，最后1次针刺结束后24 h时制备局灶性脑缺血再灌注损伤模型。于再灌注6、24和48 h时行神经功能缺陷评分；提取缺血侧脑皮质组织线粒体，采用Western blot法检测线粒体Drp1表达；电镜下观察线粒体超微结构；采用TUNEL法确定神经元凋亡率。结果与S组比较，I/R组和EA组各时间点神经功能缺陷评分和神经元凋亡率升高，线粒体Drp1表达上调（P〈0.01）；与I/R组比较，EA组再灌注各时点神经功能缺陷评分和神经元凋亡率降低，线粒体Drp1表达下调（P〈0.05）。结论电针预处理减轻大鼠脑缺血再灌注损伤的机制可能抑制Drp1活性，从而抑制线粒体过度分裂有关。

Objective To evaluate the effect of electroacupuncture（EA）preconditioning on the activity of dynamin-related protein 1（Drp1）in brain tissues during cerebral ischemia-reperfusion（I/R）in rats.Methods A total of 126 pathogen-free healthy adult male Wistar rats, weighing 250-300 g, were divided into 3 groups（n=42 each）using a random number table： sham operation group（group S）, group I/R and EA preconditioning group（group EA）. In group S, the blood vessels were only separated but not occluded.In group I/R, a nylon thread with rounded tip was inserted into the left middle cerebral artery advanced cranially until resistance was met, and middle cerebral artery occlusion was maintained for 2 h followed by reperfusion.In group EA, Baihui acupoints were stimulated with an electric stimulator（2/15 Hz disperse-dense waves, intensity 1 mA）for 30 min, lasting for 5 consecutive days, and the model of focal cerebral I/R was established at 24 h after the last stimulation.At 6, 24 and 48 h of reperfusion, the neurologic deficit was assessed and scored, the mitochondria in the cerebral cortex on the ischemic side were extracted, the expression of Drp1 in mitochondria was detected using Western blot, the mitochondrial ultrastructure was examined with an electron microscope, and neuroapoptosis was measured using TUNEL.The apoptosis rate was calculated.Results Compared with group S, the neurological deficit score and apoptosis rate were significantly increased, and the expression of Drp1 in mitochondria was up-regulated at each time point in I/R and EA groups（P〈0.05）. Compared with group I/R, the neurological deficit score and apoptosis rate were significantly decreased, and the expression of Drp1 in mitochondria was down-regulated at each time point in group EA（P〈0.05）.Conclusion The mechanism by which EA preconditioning reduces cerebral I/R injury may be related to inhibiting the activity of Drp1 and thus inhibiting the excessive fission of mitochondria in rats.