Objective: To investigate the effect of electroacupuncture (EA) on the expression of β-amyloid (Aβ) and autophagy-related proteins in hippocampal cells of Alzheimer's disease (AD) model mice, so as to explore its underlying mechanisms.
Methods: Eighteen male APP/PS1 transgenic mice (6 months old) were randomly divided into model and EA groups, with 9 mice in each group. Nine male C57BL/6 wild-type mice of the same age were chosen as the normal group. Mice in the EA group were treated with acupuncture on "Baihui" (GV20) and EA (1 Hz/50 Hz, 1 mA) on bilateral "Yongquan" (KI1), once every other day, 20 min each time for a total of 21 times. After the interventions, the spatial learning and memory ability were observed by Morris water maze test. The autophagy-related pathological changes in hippocampus were observed by transmission electron microscopy. The expressions of microtublue associated protein 1 light chain 3 (LC3) and Aβ in hippocampus were observed by immunofluorescence and the expression levels of LC3 and p62 proteins were detected by Western blot.
Results: Compared with the normal group, the escape latency was prolonged (P<0.01), the residence time in the original quadrant platform was shor-tened (P<0.05), the positive expressions of LC3 and Aβ, the expression levels of LC3Ⅱ and p62 proteins, and the ratio of LC3Ⅱ/LC3Ⅰ proteins in hippocampus were increased (P<0.01, P<0.05) in the model group. Compared with the model group, the escape latency was shortened (P<0.05), the residence time in the original quadrant platform was prolonged (P<0.05), the positive expressions of LC3 and Aβ, the expression levels of LC3Ⅱ and p62 proteins, and the ratio of LC3Ⅱ/LC3Ⅰ proteins in hippocampus were decreased (P<0.05) in the EA group. The transmission electron microscopy showed that the structure of neurons was normal in the normal group, a large number of autolysosomes and autophagosomes existed in hip-pocampal nerve cells in the model group, and only a small number of autophagosomes were observed in the EA group.
Conclusion: EA can reduce the expression levels of autophagy-related proteins LC3 and p62 in APP/PS1 transgenic mice, improve the hip-pocampal autophagy state, reduce intracellular Aβ aggregation, and thus improve the learning and memory ability.
目的：通过观察电针对阿尔茨海默病(AD)模型小鼠海马细胞内β-淀粉样蛋白(Aβ)及自噬相关蛋白表达的影响，探讨电针治疗AD的机制。方法：将18只6月龄雄性APP/PS1双转基因小鼠随机分为模型组和电针组，每组9只；以9只同月龄同性别的C57BL/6野生型小鼠作为正常对照组。电针组小鼠给予针刺“百会”及电针双侧“涌泉”，20 min/次，隔日1次，共治疗21次。采用Morris水迷宫实验观察小鼠空间学习记忆能力，透射电镜法观察小鼠海马自噬相关病理变化，免疫荧光染色法观察小鼠海马CA1区微管相关蛋白1轻链3(LC3)及Aβ的表达，Western blot法检测小鼠海马组织中LC3、p62蛋白的表达水平。结果：与正常对照组比较，模型组小鼠逃避潜伏期延长(P<0.01)，原平台象限停留时间缩短(P<0.05)，海马CA1区LC3、Aβ阳性表达均升高(P<0.01)，海马组织中LC3Ⅱ、p62蛋白表达水平及LC3Ⅱ/LC3Ⅰ比值均升高(P<0.01，P<0.05)。与模型组比较，电针组小鼠逃避潜伏期缩短(P<0.05)，原平台象限停留时间延长(P<0.05)，海马CA1区LC3、Aβ阳性表达均降低(P<0.05)，海马组织中LC3Ⅱ、p62蛋白表达水平及LC3Ⅱ/LC3Ⅰ比值均降低(P<0.05)。透射电镜结果显示，正常对照组海马神经元结构正常，模型组海马神经细胞内存在大量自噬溶酶体，电针组仅观察到少量自噬溶酶体。结论：电针可降低APP/PS1双转基因小鼠自噬相关蛋白LC3与p62的表达水平，改善其海马自噬状态，减少细胞内Aβ聚集，从而改善其学习记忆能力。.
Keywords: APP/PS1; Alzheimer’s disease; Autophagy; Electroacupuncture.