Notch信号通路在电针预处理诱导大鼠脑缺血耐受中的作用

Role of Notch signaling pathway in cerebral ischemic tolerance induced by electroacupuncture preconditioning

目的 探讨Noah信号通路在电针预处理诱导大鼠脑缺血耐受中的作用.方法 健康成年雄性SD大鼠52只,体重280～320 g,随机分为2组（n=26）：正常对照组（C组）不做任何处理;电针预处理组（EA组）于百会穴进行电针刺激（刺激条件：疏密波2/15Hz,电流强度1 mA）,30 min次,1次/d,连续5 d.最后一次电针刺激结束后24 h采用阻断单侧大脑中动脉120 min再灌注72 h的方法制备局灶性脑缺血再灌注模型.分别于缺血前即刻、再灌注24 h及再灌注72 h时采用Western blot法测定缺血侧大脑皮层Notch细胞内片段（NICD）蛋白的表达,采用实时定量PCR法测定缺血侧大脑皮层Notch通路信号分子的表达;于再灌注72 h时进行神经功能损伤评分,评分完毕后测定脑梗死体积百分比.结果 缺血前即刻两组大脑皮层Hesl mRNA及NICD蛋白表达差异无统计学意义（P〉0.05）;与缺血前即刻比较,两组再灌注24、72 h时NICD蛋白表达上调,C组再灌注72 h时Hesl mRNA 表达上调,EA组再灌注24 h时Hesl mRNA表达上调（P〈0.05）;与再灌注24 h时比较,再灌注72 h时C组Hesl mRNA及NICD蛋白表达均上调,EA组Hesl mRNA及NICD蛋白表达均下调（P〈0.05）;与C组比较,EA组缺血前即刻Notchl mRNA、Notch4 mRNA及Jagl mRNA的表达上调,再灌注24 h时Hesl mRNA及NICD蛋白表达上调,再灌注72 h时Hesl mRNA及NICD蛋白表达下调,脑梗死体积百分比降低,神经功能损伤评分升高（P〈0.05）.结论 Notch信号通路可能参与了电针预处理诱导的大鼠脑缺血耐受.

Objective To investigate the role of Notch signaling pathway in cerebral ischemic tolenmce induced by clectroacupuncture （EA） preconditioning.Methods Fifty-two adult male SD rats weighing 280-320 g were randomly divided into 2 groups（n=each）：control group（group C）and electroacupuncture preconditionig group（group EA）.Group C received no treatment.Group EA received EA at the Baihui acupoint （GV20） for 30 min a day for 5 days.Twenty-four hours after the last preconditionig,focal cerebral ischemia was induced by middle cerebral artery occlusion （MCAO） for 120 min,followed by 72 h of reperfusion.Notch intracellular domain（NICD）expression was determined by Western blot and expression of Notch1,Notch4,Jag1,and Hes1 mRNA by real-time PCR immediately before iachemia and 24 and 72 h of reperfusion.The neurological deficit was scored at 72 h of reperfusion.The infarct volumes were then determined after evaluation of the neurological deficit score .Results There was no significant difference in Hesl mRNA and NICD expression immediately before ischemia between group EA and C（P〉O.05）.NICD expression was up-regulated at 24 and 72 h of reperfusion in both groups, and Hesl mRNA expression at 72 h of reperfusion in group C and at 24 h of reperfusion in group EA was up-regulated compared with those immediately before ischemia （P 〈 0.05）. Hes1 mRNA and NICD expression was up-regulated in group C, while down-regulated in group EA at 72 h of reperfusion compared with those at 24 h of reperfusion （ P 〈 0.05 ）. Compared with group C, the expression of Notchl,Notch4 and Jag1 mRNA was up-regulated immediately before ischemia, and Hes1 mRNA and NICD expression was up-regulated at 24 h of reperfusion while down-regulated at 72 h of reperfusion in group EA（ P 〈 0.05）. EA preconditioning significantly reduced infarct volumes and increased neurological deficit scores at 72 h of reperfusion （P 〈 0.05 ）. Conclusion Notch signaling pathway may participate in cerebral ischemic tolerance induced by EA preconditioning.