交泰丸通过激活PI3K/AKT信号通路改善阿尔茨海默病模型小鼠大脑的葡萄糖代谢

Jiaotaiwan improves brain glucose metabolism in a mouse model of Alzheimer's disease by activating the PI3K/AKT signaling pathway

目的探讨交泰丸对阿尔茨海默病模型小鼠大脑胰岛素PI3K/AKT通路的影响。方法50只3月龄雄性APP/PS1双转基因小鼠随机分为5组:模型组、交泰丸低剂量组(2.1 g/kg)、交泰丸中剂量组(4.2 g/kg)、交泰丸高剂量组(8.4 g/kg)、多奈哌齐组(3 mg/kg),C57BL/6J雄性小鼠为正常组,10只/组。给药4周后,采用水迷宫和旷场实验评估各组小鼠学习记忆能力,采用HE染色、尼氏染色观察小鼠脑组织神经元病理改变,免疫组化法观察小鼠脑组织Aβ淀粉样斑块沉积情况,ELISA试剂盒测定小鼠空腹血清胰岛素水平,采用Western blot和RT-qPCR检测小鼠脑组织中Aβ42、胰岛素PI3K/AKT通路以及下游GLUTs等相关指标蛋白和mRNA表达水平。结果与正常组小鼠比较,模型组小鼠学习记忆能力受损,小鼠海马神经元细胞数量减少,排列稀疏,小鼠脑组织Aβ淀粉样斑块沉积显著增多(P<0.001),Aβ42蛋白表达水平升高(P<0.05),胰岛素抵抗指数升高(P<0.001),小鼠海马PI3K蛋白以及mRNA表达均降低(P<0.01),海马与皮质AKT蛋白表达(P<0.05)、AKT mRNA表达(P<0.001)、InR蛋白表达(P<0.05),GLUT1、GLUT3、GLUT4蛋白表达(P<0.05)及mRNA表达(P<0.001)均降低,GSK3β蛋白表达(P<0.01)及GSK3βmRNA表达(P<0.001)显著升高。与模型组比较,交泰丸各组和多奈哌齐组小鼠记忆能力明显改善,尤其是交泰丸中剂量组,小鼠海马神经元细胞数量增多,小鼠海马、皮质Aβ淀粉样斑块沉积减少(P<0.01),Aβ42蛋白表达下调(P<0.001),胰岛素抵抗指数降低(P<0.001),小鼠海马、皮质PI3K、AKT、InR、GLUT1、GLUT3、GLUT4蛋白(P<0.05)及mRNA(P<0.01)表达不同程度升高,GSK3β蛋白及mRNA表达降低。结论交泰丸可通过激活APP/PS1双转基因小鼠大脑胰岛素PI3K/AKT通路,调控其下游GLUTs表达水平,提高大脑葡萄糖代谢能力,改善小鼠学习记忆能力,延缓阿尔茨海默病发展进程。

Objective To investigate the effect of Jiaotaiwan on brain insulin-PI3K/AKT pathway in a mouse model of Alzheimer's disease(AD).Methods Fifty 3-month-old male APP/PS1 double transgenic mice were randomized into AD model group,low-,medium-and high-dose Jiaotaiwan treatment groups,and donepezil treatment group.Cognitive functions of the mice were assessed using water maze and open field tests,and neuronal pathologies were observed with HE staining and Nissl staining;immunohistochemistry was used to detect amyloid Aβdeposition in the brain.Fasting serum insulin levels of the mice were measured,and the expressions of Aβ42,insulin-PI3K/AKT pathway components and downstream glucose transporters in the brain tissue were detected with RT-qPCR and Western blotting.Results The AD mouse models exhibited obvious impairment of learning and memory abilities,significantly reduced hippocampal neurons,and obvious Aβamyloid plaques in the brain tissue with increased Aβ42 protein expression(P<0.05)and insulin resistance index,decreased hippocampal PI3K expressions,lowered expressions of AKT and InR,reduced expressions of GLUT1,GLUT3,and GLUT4,and increased expression of GSK3βin both the hippocampus and cortex.Treatment with Jiaotaiwan and donepezil both effectively improved memory ability of the mouse models,increased the number of hippocampal neurons,reduced Aβamyloid plaques and increased the expressions of PI3K,AKT,InR,GLUT1,GLUT3 and GLUT4 in the hippocampus and cortex.Conclusion Jiaotaiwan improves learning and memory abilities of APP/PS1 double transgenic mice and delay the development of AD by activating the PI3K/AKT pathway and regulating the expression levels of its downstream GLUTs in the brain.