Objective: To investigate the effect of electroacupuncture(EA) stimulation on proliferation and diffe-rentiation of endogenous neural stem cells as well as Jagged1/Notch1 pathway in AD model mice, so as to explore its mechanism underlying amelioration of AD.
Methods: A total of 40 6-week-old male APP/PS1 transgenic AD mice were randomly divided into EA group (n=20) and AD model group ( n=20), and other 20 normal C57BL/6J mice of the same age were used as the normal control group. The mice in the EA group received EA (10 Hz, 2 mA) at "Baihui"(GV20), "Fengfu"(GV16) and bilateral "Shenshu" (BL23) for 20 min, once daily, 6 days a week for 16 weeks. The mice's learning-memory ability was detected by Morris water maze tests. The Aβ senile plaques in the hippocampal CA1 region were detected by Congo red staining, the immunofluorescence double label of BrdU, neuronal nuclear antigen (NeuN) and astrocyte specific protein GFAP in dentate gyrus of hippocampus was performed for detecting the proliferation and differentiation of the endogenous neural stem cells. The expression levels of Nestin (neuron specific protein) and GFAP were detected by Western blot, and those of Jagged1 and Notch1 mRNAs and proteins in the hippocampus were detected by real-time fluorescence quantifative PCR and Western blot.
Results: Compared with the normal control group, the escape latencies at 2nd, 3rd and 4th day, and Aβ senile plaques were significantly increased (P<0.05, P<0.01), whereas the platform crossing times and time spent in the target quadrant, the expression levels of Jagged1 mRNA and Nestin protein were remarkably down-regulated (P<0.05) in the model group. Following EA intervention, the escape latencies at the 3rd and 4th day, Aβ senile plaques, immunofluorescence density of BrdU/GFAP, and GFAP protein expression were pronouncedly decreased (P<0.05, P<0.01), while the platform crossing times, platform quadrant residence time, immunofluorescence density of BrdU/NeuN, expression levels of Jagged1 and Notch1 mRNAs and proteins and Nestin protein evidently increased (P<0.05, P<0.01), suggesting an enhancement of proliferation and diffe-rentiation of endogenous neural stem cells into neurons and a suppression of the proliferation and differentiation towards astrocytes in the hippocampus.
Conclusion: EA at GV20, GV16 and BL23 can improve the learning-memory ability, promote the proliferation and differentiation of endogenous neural stem cells towards neurons and inhibit the proliferation and differentiation of endogenous neural stem cells towards astrocytes in the hippocampus, which may be achieved by regulating Jagged1/Notch1 pathway.
目的：探讨电针对阿尔茨海默病（AD）小鼠海马内源性神经干细胞增殖分化及Jagged1/ Notch1通路的影响，探讨电针治疗AD的部分机制。方法：APP/PS1双转基因小鼠随机分为电针组和AD模型组，每组20只，另以同月龄正常C57BL/6J小鼠20只作为正常对照组。电针组小鼠电针“百会”“风府”和双侧“肾俞”，每次20 min，每日1次，每周休息1 d，共治疗16周。Morris水迷宫测试检测小鼠学习记忆功能变化；刚果红染色检测小鼠海马CA1区β淀粉样蛋白（Aβ）老年斑情况；免疫荧光双标法检测小鼠海马齿状回胸腺嘧啶类似物5-溴-2-去氧胸腺嘧啶（BrdU）、神经元核抗原（NeuN）和胶质纤维酸性蛋白（GFAP）表达；荧光定量PCR法检测海马Jagged1和Notch1 mRNA表达水平；Western blot法检测小鼠海马巢蛋白（Nestin）、GFAP、Notch1和Jagged1蛋白表达水平。结果：与正常对照组比较，AD模型组小鼠第2、3、4天的逃避潜伏期延长（P<0.05），穿越原平台次数、平台象限停留时间减少（P<0.05）；海马CA1区Aβ老年斑增多（P<0.01），Jagged1 mRNA表达降低（P<0.05），Nestin蛋白表达水平降低（P<0.05）。与AD模型组比较，电针组小鼠第3、4天逃避潜伏期缩短（P<0.05）；穿越原平台次数、平台象限停留时间增加（P<0.05）；海马CA1区Aβ老年斑减少（P<0.01），海马区BrdU/NeuN双标阳性细胞表达升高（P<0.01），BrdU/GFAP双标阳性细胞表达降低（P<0.01），Nestin蛋白表达水平升高（P<0.05），GFAP蛋白表达水平降低（P<0.01）， Jagged1和Notch1 mRNA、蛋白表达水平升高（P<0.05）。结论：电针可改善AD模型小鼠的学习记忆能力、促进内源性神经干细胞向神经元方向增殖分化，抑制内源性神经干细胞向星形胶质细胞方向增殖分化，此作用可能是通过调节Jagged1/ Notch1通路实现的。.
Keywords: Alzheimer's disease; Electroacupuncture; Learning-memory ability; Neural stem cells; Notch pathway.