电针对血管性痴呆大鼠学习记忆功能和海马突触可塑性的影响

目的 观察电针对血管性痴呆(VD)大鼠学习记忆功能的影响,探讨电针治疗VD的作用机制.方法 将40只Sprague-Dawley大鼠分为假手术组、模型组、电针组和西药组,除假手术组行假手术外,其余各组建立VD大鼠模型.电针组术后给予电针百会、大椎穴治疗,药物组给予尼莫地平灌胃,均治疗10 d.采用Morris水迷宫试验检测大鼠学习记忆能力,微电极记录海马齿状回长时程增强效应,免疫组织化学染色技术观察脑组织海马突触素(Syp)染色情况.结果 与模型组比较,电针组和西药组治疗后水迷宫逃避潜伏期明显缩短(P＜0.01),相同时间内在原平台象限跨越相应平台次数明显增多(P＜0.01),高频刺激后相对群峰电位潜伏期缩短、相对兴奋性突触后电位斜率和相对群峰电位幅值增大(P＜0.05),Syp免疫阳性细胞积分光密度值显著增大(P＜0.01).结论 电针大鼠百会、大椎穴能改善大鼠学习记忆能力,其机制可能是通过促进海马Syp的表达从而增强海马突触可塑性以及加快海马神经元突触传递过程来实现.

Abstract：

Objective To investigate the effects of electroacupuncture (EA) on spatial learning and memory ability, long-term potentiation (LTP) and synaptophysin (Syp) levels in the dentate gyrus of the hippocampus.Methods Forty Sprague-Dawley rats were randomly divided into a sham-operated control group, a model group, an EA group and a medication group. A rat model of vascular dementia (VD) was established by repeated ischemia and reperfusion after pretreatment with sodium nitroprusside. EA was applied to the rat homologues of the human "Baihui" (GV20) and "Dazhui" (DU14) acupoints of the rats in the EA group for 20 min, once daily for 10 d.Morris water maze tests were conducted for evaluating the rats,learning and memory ability. LTP in the hippocampal dentate gyrus was recorded as an electrophysiological index for evaluating learning and memory. Antigenic Syp produced in hippocampal tissue was examined with immunohistochemical assays. Results In comparison the with model group, escape latency (EL) shortened and target-platform crossing times increased significantly in the EA and medication groups. After high frequency stimulation the population spike (PS) latency shortened in the EA group compared with the model group, and the excitatory postsynaptic potential (EPSP) slope and PS amplitude increased.All of these differences were statistically significant. Syp positive cells also increased significantly in the EA-treated rats. Conclusions EA can increase Syp expression and improve the learning and memory ability of rats with this model of VD. EA could facilitate the induction and maintenance of LTP in the dentate gyrus of the hippocampus through influencing synaptic transmission.

The effects of electroacupuncture on learning, memory and hippocampal synaptic plasticity in vascular dementia