运动训练对脑缺血大鼠神经功能及梗死边缘区细胞增殖与凋亡的影响

摘要

目的:探讨运动训练对急性脑缺血大鼠神经功能及脑皮质梗死边缘区细胞增殖与凋亡的影响.方法:采用改良Zea-Longa线栓法制作大脑中动脉阻塞(MCAO)模型,将大鼠随机分成运动训练组(n=15)、对照组(n=15)和假手术组(n=9).运动训练组大鼠从术后1d开始每天予以跑笼运动训练；对照组和假手术组大鼠置于普通笼内饲养,不予以任何针对性训练.3组大鼠在造模术后1d、8d和15d分别进行神经功能评分(mMSS),并采用Ki67免疫荧光、TUNEL法分别观察脑皮质梗死边缘区细胞增殖、凋亡,以Western印迹法检测Bcl-2与Bax蛋白表达的情况.结果:在造模术后8d和15d,训练组大鼠的神经功能评分(mNSS)均明显优于对照组,差异有显著性意义(P＜0.05)；免疫荧光结果显示,训练组大鼠脑皮质梗死边缘区Ki67阳性细胞增加,且以造模术后8d最明显,与对照组相比,差异有显著性意义(P＜0.05)；在造模术后8d和15d,训练组TUNEL阳性细胞数较对照组明显减少,同时,训练组梗死边缘区Bcl-2的表达高于对照组,Bax的表达低于对照组.结论:运动训练能够促进急性脑梗死大鼠神经功能的恢复,其机制可能与促进皮质梗死边缘区细胞增殖、减少细胞凋亡有关.%Objective:To study the effects of exercise training on neural function and cell proliferation as well as cell apoptosis in the peri-infarction region in rats with acute cerebral infarction.Method:Permanent cerebral ischemia was induced by left middle cerebral artery occlusion (MCAO) in adult Sprague-Dawley rats.Rats were randomly divided into a exercise training group(n=15),a control group and a sham surgery group.Wheel running was administered to the rats of exercise training group at day 1 after MCAO.The rats in the latter two groups were fed in standard cages without any special training exercise.Their neurological functions were measured with modified neurological severity score(mNSS) at the 1std,8thd and 15thd after MCAO.Ki67 and TUNEL method were used to observe cell proliferation and apoptosis,and Western blotting was used to detect the expressions of Bcl-2 and Bax in the peri-infarction region.Result:The rats in exercise training group showed significantly better neurological function at 8d and 15d post MCAO(P＜0.05),and significantly less TUNEL-positive cells(P＜0.05) as compared with control group.Ki67 cell proliferation increased obviously in exercise training group versus those in control group,especially at day 8.Moreover,Western blotting result showed up-regulation of Bcl-2 and down-regulation of Bax in exercise training group.Conclusion:Exercise training can facilitate functional recovery after cerebral infarction in rats,and this may be partially attributed to the increase of cell proliferation and the decrease of cell apoptosis.