缺血再灌注后蛋白集聚与皮层神经元延迟性死亡的关系

The relationship between protein aggregation and delayed neuronal death in the cortex after ischemia-reperfusion

目的探讨缺血再灌注后蛋白聚集与大鼠皮层神经元延迟性死亡的关系。方法采用20 min全脑缺血的大鼠模型。按照再灌注时间分为5组:假手术组,0.5 h恢复组,4 h恢复组,24h恢复组,72 h恢复组。采用HE染色光镜下观察缺血再灌注后皮层神经元的延迟性死亡。应用透射电子显微镜观察细胞胞浆内蛋白聚集物。Westernblot分析泛素蛋白标记的蛋白聚集物在神经元内的含量变化。结果HE染色显示缺血再灌注72 h后,可见部分皮层神经元死亡。透射电镜显示再灌注4 h后神经元的胞浆内形成了蛋白聚集物。Western blot分析显示,与假手术组相比较,再灌注后0.5 h被泛索标记的蛋白聚集物便开始显著增加,再灌注后4 h和24 h达到峰值,再灌注后72 h含量开始减少。但仍然高于假手术组。结论蛋白聚集是导致缺血再灌注后神经元延迟性死亡的一个重要因素。

Objeetive To investigate the relationship between protein aggregation and delayed neuronal death in the cortex of rats after ischemia-reperfusion. Methods The rat models after 20 min global cerebral ischemia were divided into five groups according to the reperfusion period： sham-operation group, 0.5 h recovery group, 4 h recovery group, 24 h recovery group and 72 h recovery group. HE staining under the light microscope was used to observe delayed neuronal death in the cortex after ischemia-reperfusion; the transmission electron microscope was used to observe protein aggregations that formed in the cytoplasm of cortical neurons. The Western blot was used to analyze the changes in the content of intra-neuronal protein aggregations labeled with the ubiquitin protein. Results HE staining showed that some cortical neurons died after 72 h ischemia-reperfusion; the transmission electron microscope indicated that protein aggregations developed in the cytoplasm of neurons after 4 h reperfusion; the Western blot analysis found that compared with the sham-operation group, the protein aggregations labeled with ubiquitin began to increase significantly after 0.5 h reperfusion, reached the peak value respectively after 4 h and 24 h reperfusion, and began to decrease after 72 h reperfusion, but still higher. Conclusion Protein aggregation plays an important role in delayed neuron death after ischemia-reperfusion.