经颅直流电刺激促进缺血性脑卒中大鼠海马区神经发生

Transcranial direct current stimulation promoted neurogenesis in hippocampus of rats after ischemic stroke

目的: 探讨经颅直流电刺激( transcranial direct current stimulation,tDCS) 对缺血性脑卒中大鼠海马区神经干细胞( neural stem cell,NSC) 增殖和分化的影响。方法: 成年Sprague-Dawley 大鼠50 只,在头部电极植入后3d,进行大脑中动脉栓塞( middle cerebral artery occlusion,MCAO) 手术,通过Zea Longa 评分筛选中度脑损伤大鼠并随机分为两组: tDCS 处理组( n = 12) 和假tDCS 处理组( Sham 组,n = 12) 。tDCS 组大鼠接受连续5 d 的阴极tDCS处理( 500 μA,15 min/次,1次/d);Sham组仅与tDCS 刺激仪连接但无电流输出。于MCAO 术后3 d( 3 day post operation,POD 3) 和POD 7 断头取脑,利用免疫荧光染色观察海马和皮层中Nestin^+、DCX^+ 及NG2^+ 细胞; 采用酶联免疫吸附实验检测海马区脑源性神经营养因子( brain derived neurotrophic factor,BDNF) 含量。结果: 在POD 3,与Sham 组相比, tDCS 组大鼠损伤侧海马中Nestin^+ 细胞数量显著增加( P<0.01) ,BDNF 含量显著增加( P<0.05) 。在POD 7,与Sham组相比,tDCS 组大鼠损伤侧海马中DCX^+ 及NG2^+ 细胞数量显著增加( P<0.01) 。结论: tDCS 可促进缺血性脑卒中大鼠海马区NSCs 增殖及向神经元和少突胶质细胞方向分化。

Objective: To investigate the effects of transcranial direct current stimulation ( tDCS) on proliferation and differentiation of neural stem cells ( NSCs) in hippocampus of rats after ischemic stroke.Methods: 50 adult male Sprague-Dawley rats were used to receive a surgery of middle cerebral artery occlusion ( MCAO) three days after epicranial electrodes implantation.Subsequently,animals with moderate neurological deficits were selected and randomly divided into two groups: tDCS group ( n = 12) and sham tDCS group ( Sham,n = 12) .Animals in tDCS group underwent 5 consecutive days cathodal tDCS ( 500 μA,15 min,once a day) and rats in Sham group were only connected to the tDCS stimulator but without current output.The animals were sacrificed on 3 day post MCAO operation ( POD 3) and POD 7.Then,Nestin^ + ,DCX^+ and NG2 ^+ cells in hippocampus and cortex were observed by immunofluorescence staining.The level of brain derived neurotrophic factor ( BDNF ) in hippocampus was detected by enzyme-linked immunosorbent assay ( ELISA) .Results: Compared with Sham group,the number of Nestin + cells and the level of BDNF in hippocampus significantly increased in tDCS group ( P<0.01,P<0.05,respectively) on POD 3.In addition,compared with Sham group,the number of DCX ^+ and NG2^ + cells in hippocampus significantly increased in tDCS group on POD 7 ( P<0.01) .Simultaneity,those immature cells above also obviously increased in cortex with ischemic injury ( P<0.01) .Conclusion: tDCS could promote the proliferation and differentiation of NSCs in the hippocampus of rats after ischemic stroke.