β-淀粉样蛋白对阿尔茨海默病大鼠脑局部神经元超微结构的影响

Ultrastructural changes of focal neurons after amyloid-beta protein injected into meynert nucleus in rat

目的探讨Meynert核注射β-淀粉样蛋白(Aβ)后对大鼠脑神经细胞超微结构的影响及其可能机制。方法将1μlAβ1-40(10μg/μl)在立体定向仪下注入大鼠右侧Meynert核,分别于1、4周时用透射电镜观察脑组织中神经细胞超微结构。结果Aβ注射1周后,实验组Meynert核、海马区和皮层区均可见一些神经细胞核染色质浓缩成团块并见边聚现象,神经细胞有发生凋亡的趋势;4周时可见典型的神经细胞凋亡;突触结构数量减少。正常对照组和假手术组超微结构基本正常。结论Aβ注入Meynert核能引发CNS神经细胞凋亡和突触结构减少,可能是AD记忆障碍和痴呆形成的重要机制之一。

Objective To investigate the ultrastructural changes of focal neurons after amyloid beta protein injected into Meynert nucleus in rats.Methods Aβ1-40(10μg) was microinjected into the right Meynert nucleus of rats,1 week and 7weeks later, ultrastructure of neurons and synape was observed under transmission electron microscopy(TEM).Results In experimental group, the TEM examination revealed the chromatin of many neurons in the Meynert nucleus,hippocampus and cortex subfieds were condensed, compact patches to become apoptosis at 1 week.The apoptostic neurons were showed at 4 week. The numbers of synapes were obviously declined. Conclusions Aβ could induce the neuronal apoptosis and decreased synapes in the rat brains,may be one of important mechnisms of memory disorder and AD formation.