单次电针预处理诱导大鼠局灶性脑缺血耐受的时程

目的 探讨单次电针预处理能否诱导局灶性脑缺血耐受及其时程。方法 48只健康雄性SD大鼠(280～320g),随机分为6组(n=8):对照组和电针1～5组(EA1～5)。对照组未行任何预处理;电针1～5组分别在电针刺激百会穴30min后0.5、1、2、3和24 h给予局灶性脑缺血。采用颈内动脉尼龙线线栓法致大脑中动脉栓塞(120 min)模型,观察再灌注后24 h时神经功能损害并取大脑行TTC染色以测量脑梗死容积。结果术后动物均存活。电针刺激百会穴30 min后2 h和24 h给予局灶性脑缺血,再灌注24 h时神经功能缺陷评分明显低于对照组(P<0.05),脑梗死容积明显小于对照组(P<0.01),其它时间点与对照组差异无显著性。结论 单次电针刺激百会穴30 min,可诱导双相大脑局灶性缺血耐受,即急性缺血耐受出现在预处理后2 h,延迟缺血耐受出现在预处理后24 h。

Rapid and delayed tolerance to focal cerebral ischemia induced by pretreatment with single electroacupuncture in rats

Objective To determine whether rapid and delayed tolerance to focal cerebral ischemia can be induced by pretreatment with single electroacupuncture (EA) at the Baihui acupoint in rats. Methods Forty-eight healthy male SD rats weighing 280-320 g were randomly divided into 6 equal groups with 8 animals in each group: (1) control group received no pretreatment before focal cerebral ischemia; (2) electroacupuncture group was further divided into 5 groups in which EA was performed at Baihui acupoint and electric stimulation was maintained for30min0.5 h(EAl),1 h(EA2),2 h(EA3),3 h(EA4) or 24 h(EA5) before focal cerebral ischemia. The animals were anesthetized with isoflurane and spontaneous respiration was maintained. Middle cerebral artery occlusion (MCAO) was performed using a nylon thread with a rounded tip inserted into internal carotid artery and thread cranially until resistance was felt. MCAO was maintained for 2 h, then the nylon thread was withdrawn to allow reperfusion . After MCAO the animals were observed for 24 h for neurological deficits which were assessed by a 0-5 grade scoring system (0 = no deficit, 5 = death) . The animals were then sacrificed and brain was immediately removed for estimation for the size of cerebral infarction. Results There were significantly less neurological deficits and the size of infarction was smaller in group EA3 and EA5 than those in control group. There were no significant differences in neurological deficits and size of infarction between group EA1,EA2,EA4 and control group. Conclusion Pretreatment with single electroacupuncture stimulation for 30 min at Baihui acupoint can induce rapid and delayed tolerance to focal cerebral ischemia. Rapid tolerance develops 2 h after pretreatment while delayed tolerance develops 24 h after pretreatment.