电针刺激神经干对脑缺血再灌注后不同时期皮层BDNF mRNA表达的影响

Expression of brain derived neurotrophic factor after nerve trunk stimulation by electroacupuncture in rats with cerebral ischemia/reperfusion

目的 观察脑缺血再灌注大鼠脑源性神经营养因子 (BDNF)的动态变化过程及电针刺激神经干对BDNF表达的影响。方法 共选取成年健康雌性Wistar大鼠 68只 ,采用线栓法建立脑缺血再灌注动物模型 ,并随机分为对照组 (4只 )、MCAO组 (3 2只 )及神经干电针刺激组 (3 2只 )。神经干电针刺激组大鼠于再灌注后 2h ,6h ,12h ,2 4h ,2d ,3d ,7d及 14d时各进行 1次神经干电针刺激。利用原位杂交法观察上述时间点各组大鼠脑皮层BDNFmRNA表达的时程变化过程。结果 脑缺血 1h再灌注 2h ,6h ,12h ,2 4h ,2d及 3d时 ,MCAO组与对照组比较 ,前者缺血侧脑皮层BDNFmRNA阳性细胞数量显著增多 (均P <0 .0 1) ,并且于再灌 2h及再灌 2 4h时分别出现峰值 ,如再灌 2h时的BDNFmRNA含量显著高于再灌 6h及再灌 12h时的BDNFmR NA含量 ,而再灌 2 4h时的BDNFmRNA含量则显著高于其它各时间点的BDNFmRNA含量 (均P <0 .0 5 )。经电针刺激神经干后 ,大鼠在缺血再灌 2h以后的各时间点里 ,其缺血侧脑皮层BDNFmRNA阳性细胞数量均显著多于MCAO组及对照组 (均P <0 .0 5 )。结论 电针刺激缺血再灌注大鼠神经干 ,可显著增强其缺血侧脑皮质BDNFmRNA的表达 ,可能是电针刺激发挥脑保护效应的重要机制之一。

Objective To observe the expression of brain derived neurotrophic factor(BDNF) mRNA after nerve trunk stimulation by electroacupuncture in rats' cortex with cerebral ischemia/reperfusion. Methods The MCAO model was established by ligation of the artery for 1 hour, and then reperfusion was conducted for 2h, 6h, 12h, 24h, 2d, 3d, 7d and 14d.The expression of BDNF mRNA after the cerebral ischemia/reperfusion injury (MCAO group) was observed and comparison was made between the electroacupuncture group and the control group. Results The number of cells with positive expression of BDNF mRNA in the cortex after 2h, 6h, 12h, 24h, 2d and 3d of reperfusion was more than that in the control group (all P<0.01), but after 7d and 14d of reperfusion,there had no difference between the two groups (all P>0.05). At 2h of reperfusion, the amount of the positive cells peaked and was much more than that at the 6h and 12h time points (P<0.05). At 24h reperfusion, the amount of the positive cells had reached another apexes and much more than the other time points respectively (P<0.05).In the electroacupuncture group, at 2h reperfusion,the number of the positive cells demonstrated no significant increase when compared with that of the MCAO group (P>0.05),but after 6h reperfusion, a significant increase of expression of BDNF mRNA was observed against the MCAO group and control group, and the increase lasted to 14d after reperfusion. Conclusion Nerve trunk stimulation with electroacupuncture could improve and maintain the expression of BDNF mRNA for a long time, and this might contribute to the protection effect of electroacupuncture against the brain ischemia/reperfusion injury.