脑梗死后自发性高血压大鼠脑内Nogo-A mRNA的表达

目的:成年哺乳动物中枢神经再生能力低下的重要原因之一是由于环境中大量存在生长抑制因子,其中神经突起生长抑制因子Nogo-A具有最强烈的神经生长抑制作用,本实验观察Nogo-AmRNA在自发性高血压大鼠实验性脑梗死后脑内表达水平及部位的改变。方法:采用自发性高血压大鼠(SHR),按Nagasava方法行大脑中动脉栓塞术,分别于术后3d及14d取脑,并用原位杂交免疫组化技术,显示脑梗死前后及不同时相脑内Nogo-AmRNA表达的水平及部位的改变。结果:脑梗死后3d,Nogo-AmRNA表达水平较低,仅分布于皮层、基底节及海马等部位,病灶及边缘区均未见明显表达阳性信号,脑梗死14d后,Nogo-AmRNA表达在脑内明显升高。以病灶边缘区较明显,白质内表达也较多。结论:脑内Nogo-AmRNA表达在脑梗死急性期并不明显升高,但在第14天可见明显升高,病灶边缘也有明显表达。

The expression of Nogo-A mRNA in brains of experimental infarction of spontaneous hypertensive rats

AIM:One of the most important factors for lack of regeneration in the central nervous system in adult mammalian is the extensively existent of nerve growth inhibitors. Among all those, the Nogo A showed the most intensely inhibition in nerve growth. The experiment is designed to observe the neurite growth inhibitory factor Nogo A mRNA expression in the brains of SHR underwent experimental focal infarction. METHODS:The Nagasawa's model of middle cerebral artery occlussion was employed in spontaneous hypertensive rats(SHR) and the brains were obtained at 3 or 14 d after the MCAO separately. We also usd in situ hybridization to show the Nogo A mRNA expression in the brains. RESULTS: It was showed that the Nogo A mRNA expression in brains after 3 days of MCAO was comparatively lower both in the center areas and the penumbra of the infarction than normal uninfarcted brian, but it was greatly elevated at 14 days after MCAO. The cells expressing Nogo A mRNA were small and round and was located both in penumbra and the center of the infarction. CONCLUSION:The expression of Nogo A mRNA is elevated in the brains underwent 14 days of experimental focal cerebral infarction in SHR.