大鼠脑缺血/再灌注损伤后神经再生与Nogo-A蛋白、GAP-43基因表达的关系

Relationship of Expression of Nogo-A Protein and GAP-43 Gene with Nerve Regeneration after Cerebral Ischemia/Reperfusion Injury in Rats

目的:探讨大鼠脑缺血/再灌注损伤后神经轴突生长抑制因子(Nogo-A)蛋白及生长相关蛋白-43(GAP-43)基因参与神经再生的表达机制。方法:成年健康雄性Wistar大鼠162只,随机分为TUNEL组、Nogo-A组和GAP-43组各54只,各组按照实验要求再随机分为假手术组(A)大鼠6只和缺血1h再灌注(B)大鼠48只,B根据再灌注后2、6及12h,1、2、3、7和14d各6只,采用改良线栓法成功制备各组中B大鼠脑中动脉闭塞再灌注模型(MCAO),利用免疫组织化学方法检测神经细胞凋亡、Nogo-A蛋白和GAP-43基因在海马、皮质和纹状体区的表达并观察脑缺血半影区神经元再生以及梗死灶修复的动态变化。结果:3组中A大鼠在海马、皮质和纹状体区仅见少量凋亡神经细胞以及Nogo-A蛋白和GAP-43基因表达。B大鼠造模成功后2h点阳性细胞表达均开始增加,3d时凋亡细胞、Nogo-A蛋白和GAP-43基因表达达高峰;14d时凋亡细胞呈显著降低,Nogo-A蛋白表达降至最低水平,而14d时GAP-43基因呈较低表达(均P<0.05)。结论:Nogo-A蛋白表达对神经元轴突再生具有抑制作用;而GAP-43基因表达能够促进神经可塑性再生。

Objective：To investigate the relationship between the expression of Nogo-A protein and growth-associated protein （GAP）-43 gene with nerve regeneration after cerebral ischemia/reperfusion injury in rats. Methods：The healthy adult male Wister rats （162） were randomly divided into TUNEL group,Nogo-A group and GAP-43 group （n=54 each）,and they were subdivided randomly into sham-operation group （A） and ischemia-1 h/reperfusion 2 h,6 h,12 h,24 h,48 h,3 day,7 day,14 day groups （n=6,each）. By using improved thread occlusion method,the models of intraluminal middle cerebral artery occlusion （MCAO） and reperfusion were induced. Immunohistochemistry was used to detect the apoptosis of neurons,and the expression of Nogo-A protein and GAP-43 mRNA in hippocampus,cortical area and striatal area,and observe the changes in dynamic state of neurons regeneration and infarct focus repair in cerebral ischemic penumbra. Results：There were few apoptostic neurons and weak expression of Nogo-A protein and GAP-43 mRNA in hippocampus,cortical area and striatal area in sham-operation group. In ischemia/reperfusion group,the number of positive cells and expression levels were began to significantly increase at the 2nd h,reached the peak at the 3rd day,and at the 14th day,the number of apoptostic cells was significantly reduced,the expression of Nogo-A protein reached the lowest,and GAP-43 mRNA was weakly expressed （P0.05）. Conclusion：The expression of Nogo-A protein can inhibit neuron axon regeneration,and that of GAP-43 mRNA can promote neural plasticity regeneration.