低频电刺激对急性脑梗死大鼠脑bFGF、EGF表达和内源性神经干细胞增殖的影响

The effect of low frequency electrical stimulation on basic fibroblast growth factor and epidermal growth factor expression and on endogenous neural stem cell proliferation in the brains of rats with acute cerebral infarction

目的 观察低频电刺激（LFES）治疗对急性脑梗死大鼠脑部内源性神经干细胞（NSC）和碱性成纤维细胞生长因子（bFGF）、表皮生长因子（EGF）表达的影响,探讨LFES治疗改善脑梗死后神经功能的机制.方法 选择成年Sprague-Dawley大鼠,用随机数字表法分为LFES治疗组、安慰刺激组和假手术组,每组又根据观察时间点分为治疗第3,7,14天3个亚组.LFES治疗组和安慰刺激组大鼠制作急性大脑中动脉梗死模型.术后第3天,LFES治疗组开始接受LFES治疗（频率30 Hz,脉宽250μs,强度为3 mA,每次10 min）,观察在治疗第3天、第7天、第14天大鼠海马齿状回和室管膜下区NSC巢蛋白的表达水平,检测梗死侧脑组织bFGF、EGF总蛋白和mRNA的表达量,同时采用网屏试验评价大鼠运动功能.结果 LFES治疗组大鼠巢蛋白阳性细胞数在治疗第7天、第14天明显高于安慰刺激组（P＜0.05）;梗死侧脑组织bFGF、EGF总蛋白和mRNA表达量在治疗第7天、第14天明显高于安慰刺激组（P＜0.05）;LFES治疗组网屏试验评分在治疗第14天明显高于安慰刺激组（P＜0.05）.结论 LFES能促进急性脑梗死大鼠脑部内源性NSC的增殖和bFGF、EGF的表达,并改善大鼠运动功能,增强脑的可塑性.

Objective To observe the effects of low frequency electrical stimulation （LFES） on the proliferation of endogenous brain neural stem cells （NSCs） and on the expression of basic fibroblast growth factor （bFGF）and epidermal growth factor （EGF） in rats with acute cerebral infarction; to explore the therapeutic mechanism of LFES in improving neural function. Methods Fifty-four rats were randomly divided into a LFES group, a placebo stimulation group and a sham-operated group. Each group was further divided into 3rd day, 7th day and 14th day subgroups, with 6 rats in each subgroup. An acute cerebral infarction model was induced in the rats of the LFES and placebo stimulation groups by middle cerebral artery occlusion （MCAO）. Three days after the operation, rats in the LFES group began LFES treatment （frequency 30 Hz, pulse width 250 μs, current intensity 3 mA, 10 min/d） ,while the placebo stimulation group was treated identically but without electricity. The rats in the sham-operated group had no special treatment. The expression of nestin positive cells in the subgranular zone of the hippocampus and the subventricular zone was detected by immunohistochemical staining. The expression of bFGF, EGF proteins and mRNA in the ischemic hemisphere was detected by Western blotting and RT-PCR analysis. A screen test was applied to evaluate motor function. Results Nestin-positive cells in the subgranular and subventricular zones of rats in the LFES group increased significantly more than in the placebo stimulation group at the 7th and 14th day. The expression of bFGF, EGF proteins and mRNA in the ischemic hemisphere was up-regulated compared to the placebo stimulation group at the 7th and 14th day. At the 14th day a difference in motor function was observed in rats in the LFES group compared with the placebo stimulation group. Conclusion LFES can promote the proliferation of endogenous brain NSCs and the expression of bFGF and EGF in rats with acute cerebral infarction. It can also improve motor function and enhance neural plasticity in the brain.