局灶性脑缺血后神经干细胞增殖及GDNF表达变化的实验研究

目的研究局灶性脑缺血后大鼠脑内神经干细胞(NSCs)增殖情况及与胶质细胞源性神经营养因子(GDNF)表达变化的关系。方法将24只SD大鼠随机分为假手术组和模型1组、模型2组、模型3组各6只,后三组用大脑中动脉栓塞法(MCAO)制备局灶性脑缺血模型,分别于术后3、7、14 d处死;假手术组除不以尼龙线阻塞大脑中动脉起始部外,其他操作与模型1组相同。采用免疫组化染色法观察5-溴脱氧尿嘧啶核苷(BrdU)标记的细胞及巢蛋白(Nestin)、GDNF阳性细胞表达,BrdU/Nestin免疫荧光双标法观察NSCs变化。结果模型2组损伤侧脑室下层(SVZ)BrdU阳性细胞显著多于假手术组(P<0.05),模型3组与假手术组相似;模型2、3组皮层梗死灶周围BrdU阳性细胞均显著多于假手术组(P<0.01、0.05);模型1、2组皮层梗死灶周围Nestin阳性细胞均显著多于假手术组(P均<0.01),BrdU/Nestin免疫荧光双标显示BrdU阳性细胞几乎均为Nestin阳性;模型2、3组皮层梗死灶周围GDNF阳性细胞均显著多于假手术组(P均<0.05)。结论大鼠局灶性脑缺血后3～14 d内源性NSCs增殖加快,GDNF表达增加可能对其起促进作用。

Experimental study on the changes of neural stem cell proliferation and GDNF expression after focal cerebral ischemia

Objective To investigate the neural stem cells(NSCs) proliferation and itsrelation with glialcellline-derived neurotrophic factor(GDNF)expression after focal cerebral ischemia.Methods Total of 24 SD rats were divided into sham group and model 1 group,model 2 group,model 3 group,with 6 in each,the later three groups were made focal cerebral ischemia model by middle cerebral artery occlusion(MCAO),then were executeded 3,7 and 14 days after operation;the sham group was treated as the above groups,but middle cerebral artery was not blocked.The protein expression of BrdU,Nestin and GDNF were detected by immunohistochemical method,the NSCs was identified by BrdU/Nestin immunoflurensent double label.Results Compared with the sham group,the BrdU positive cells were significantly increased in the injuried lateral subventricular zone(SVZ) of model 1 and 2 groups(both P<0.05),which in the model 3 group was similar;the BrdU positive cells of the cortex around the infarction focus in the model 2 and 3 groups were increased significantly(P<0.01 or 0.05);the Nestin positive cells in the injuried lateral cortex of the model 1 and 2 groups were increased significantly(both P<0.01),immunofluresent double label showed that the BrdU positive cells almost were Nestin positive;the GDNF positive cells were significantly increased in the injuried lateral(both P<0.05).Conclusion The proliferation of endogenous NSCs accelerates 3-14 ds after focal cerebral Ischemia,which may be promoted by increase of GDNF expression.