电针对快速老化小鼠认知功能及海马CA1区锥体神经元树突结构的影响

Effect of Electroacupuncture on Cognitive Function and the Dendritic Structures of Pyramidal Neurons in Hippocampal CA1 Region in Senescence-accelerated Mouse

目的探讨电针刺激对快速老化模型小鼠(SAMP8)认知功能和海马CA1区锥体细胞树突结构的影响。方法选取SAMP8小鼠16只,随机分为模型组和治疗组,每组8只;另以8只正常老化SAMR1小鼠作为对照组。对照组和模型组不做任何处理。治疗组小鼠接受电针刺激治疗,取百会、肾俞、太溪穴,连续治疗8周。采用Morris水迷宫实验检测小鼠的认知功能;Golgi染色观察海马CA1区锥体神经元树突长度和数目,Western blot法检测海马突触后致密蛋白(PSD95)、脑源性神经营养因子(BDNF)、酪氨酸激酶受体B(TrkB)、Ras同系物家族成员A(RhoA)和Rho关联卷曲螺旋蛋白激酶2(ROCK2)蛋白的表达。结果与对照组比较,模型组逃避潜伏期明显延长,跨平台次数、基底和顶端树突长度及分支数目明显减少,PSD95、BDNF和TrkB蛋白表达水平明显下降,而RhoA和ROCK2蛋白表达水平明显升高(P<0.05);与模型组比较,治疗组逃避潜伏期明显缩短,跨平台次数、基底和顶端树突长度及分支数目均明显增加,PSD95、BDNF和TrkB蛋白表达水平明显升高,而RhoA和ROCK2表达水平明显下降(P<0.05)。结论电针可以明显改善SAMP8小鼠的认知功能,并增加海马CA1区树突长度和分支数目。树突可能是电针治疗阿尔茨海默病的靶点。

Objective To investigate the effect of electroacupuncture on cognitive function and the dendritic structures of pyramidal neurons in hippocampal CA1 region in senescence-accelerated mouse-prone 8(SAMP8)mice.Method Sixteen SAMP8 mice were randomized to model and treatment groups,8 rats in each group.Another 8 normal SAMR1 mice constituted a control group.The control and model groups were not treated.The treatment group received electroacupuncture at selected points Baihui(GV20),Shenshu(BL23)and Taixi(KI3)for 8 consecutive weeks.The cognitive function of the mice was assessed using the Morris water maze test.The expressions of postsynaptic density protein-95(PSD-95),brain-derived neurotrophic factor(BDNF),tyrosine kinase receptor B(TrkB),Ras homolog gene family member A(RhoA)and Rhoassociated coiled-coil containing protein kinase 2(ROCK2)were determined using Western blot.The length and number of dendrites of pyramidal neurons in hippocampal CA1 region were measured using Golgi staining.Result Escape latency lengthened significantly,the number of platform crossing,and the length of basal and apical dendrites and the number of branches decreased significantly,and the expressions of PSD-95,BDNF and TrkB declined significantly but the expressions of RhoA and ROCK2 increased significantly in the model group compared with the control group(P<0.05).Escape latency shortened significantly,the number of platform crossing,and the length of basal and apical dendrites and the number of branches increased significantly,and the expressions of PSD-95,BDNF and TrkB increased significantly but the expressions of RhoA and ROCK2 declined significantly in the treatment group compared with the model group(P<0.05).Conclusion Electroacupuncture at selected points Baihui,Shenshu and Taixi can markedly improve cognitive function and increase the length of dendrites and the number of branches in hippocampal CA1 region in SAMP8 mice.The dendrite may be a target for electroacupuncture treatment of AD.