不同月龄APP/PS1双转基因AD小鼠海马神经元线粒体的动态变化

Dynamic changes of hippocampal neuron mitochondria in APP/PS1 double transgenic Alzheimer’s disease mice at different months

摘要:

目的： 检测不同月龄APP/PS1双转基因阿尔茨海默病（Alzheimer’s disease，AD）模型小鼠海马神经元中线粒体自噬的动态变化，并探讨其意义。方法： 选取20只雄性APP/PS1双转基因AD小鼠为研究对象，分为3月龄组、6月龄组、9月龄组和12月龄组，以C57小鼠为对照组。获取海马组织，通过电镜观察海马区神经元中线粒体的形态变化，用Western blot检测自噬相关蛋白LC3和P62的表达水平；线粒体自噬相关蛋白PINK1、Parkin和Miro1的表达水平；线粒体外膜蛋白Tom20的表达水平。结果： 电镜观察结果显示：随着月龄增大，APP/PS1双转基因AD小鼠海马区神经元中线粒体损伤的病理变化呈逐渐加重的过程，即线粒体明显水肿、透明，嵴排列不规则，断裂，甚至消失。Western blot结果显示，与野生小鼠组比较，LC3、P62、PINK1和Parkin蛋白表达水平在6月龄组、9月龄组和12月龄组小鼠中明显增高（P<0.05），而Miro1蛋白却明显降低（P<0.05），Tom20的表达水平无明显差异（P>0.05）。结论： 随着APP/PS1双转基因AD小鼠月龄的增加，其海马区神经元线粒体病理改变呈动态，线粒体自噬呈动态增强但伴随线粒体清除障碍。

Abstract:

Objective: To detect the dynamic changes of mitochondria in hippocampal neurons of APP/PS1 double transgenic Alzheimer’s disease (AD) mice at different months and explore its significance. Methods: Twenty male APP/PS1 double transgenic AD mice were selected and divided into 3-month-old group, 6-month-old group, 9-month-old group and 12-month-old group, with C57 mice as the control group. The morphological changes of mitochondria in hippocampal neurons were observed by electron microscope. Western blot was used to detect the expression levels of autophagy-related proteins LC3 and P62, the expression levels of mitochondrial autophagy-related proteins PINK1, Parkin and Miro1, and the expression levels of mitochondrial outer membrane protein Tom20. Results: Electron microscopy study showed that the pathological changes of mitochondria damage in hippocampus neurons of APP/PS1 double transgenic AD mice were gradually aggravated with the increase of months, namely that, mitochondria showed obviously edema, transparent and irregularly arranged, broken or even disappeared cristae. Western blot results showed that compared with the wild mouse group, the expression levels of LC3, P62, PINK1 and Parkin protein were significantly increased in 6-month-old, 9-month-old and 12-month-old mice (P<0.05), while Miro1 protein was significantly decreased (P<0.05), and the expression level of Tom20 had no statistical significance (P>0.05). Conclusion: With the increase of age, the pathological changes of mitochondria in hippocampal neurons are dynamic in APP/PS1 double transgenic AD mice. Mitophagy is dynamically enhanced but accompanied by mitochondrial clearance obstacles.