不同针刺量对大鼠脑缺血后突触可塑性的影响

Effect of Acupuncture at Different Doses on Synaptic Plasticity of Rats After Cerebral Ischemia

【目的】观察不同针刺量对脑缺血后海马齿状回(DG)突触可塑性的影响。【方法】选用Wistar大鼠36只,随机分为假手术组、缺血模型组、治疗1组(每日针刺1次)、治疗2组(每日针刺2次),采用热凝闭大鼠大脑中动脉法复制局灶性脑缺血模型,治疗1、2组给予电针百会、大椎穴治疗。观察不同针刺次数对脑缺血后DG区突触可塑性的影响。【结果】与假手术组比较缺血模型组兴奋性突触后电位(EPSP)、群峰电位(PS)的输入/输出曲线(I/O曲线)幅度显著降低(P<0.05);与缺血模型组比较治疗1组EPSP、PS的I/O曲线显著升高(P<0.01或P<0.05),与假手术组比较无显著性差异(P>0.05)。与缺血模型组比较治疗2组EPSP、PS的I/O曲线显著升高(P<0.05),与假手术组比较EPSP的I/O曲线幅度降低(P<0.05),而PS的幅度无显著性差异(P>0.05);与治疗1组比较治疗2组EPSP的I/O曲线幅度降低(P<0.05),PS的幅度无显著性差异(P>0.05)。EPSP的长时程增强(LTP)幅度缺血模型组较假手术组显著升高(P<0.05),两个治疗组较假手术组显著升高(P<0.05),与缺血模型组比较及组间比较均无显著性差异(P>0.05)。PS的LTP幅度缺血模型组较假手术组显著降低(P<0.05),两个治疗组显著高于缺血模型组(P<0.05),与假手术组比较及组间比较均无显著性差异(P>0.05)。EPSP的长时程抑制(LTD)幅度缺血模型组较假手术组降低(P<0.05),两个治疗组EPSP的LTD幅度较假手术组显著降低(P<0.05),与缺血模型组比较及组间比较均无显著性差异(P>0.05)。缺血模型组PS的LTD幅度与假手术组比较无显著性差异(P>0.05),治疗1组PS的LTD幅度与假手术组比较显著升高(P<0.05),与缺血模型组比较无显著性差异(P>0.05);治疗2组与其他3组比较均无显著性差异(P>0.05)。【结论】针刺对缺血引起的海马DG区EPSP、PS的I/O曲线幅度变化起保护作用,能修复缺血造成的海马DG区PS的LTP诱导的损害,而不同针刺量对改变脑缺血后海马的LTP诱导方面的作用无显著性差异。

Objective To observe the effect of acupuncture at different doses on synaptic plasticity of dentate gyrus（DG） in rats after cerebral ischemia.Methods Rats models of focal cerebral ischemia were induced by occlusion of cerebral middle artery with heat.Thirty-six Wistar rats were randomized into pseudo-operation group,model group,treatment group 1（electro-acupuncture on acupoints of Baihui and Dazhui,one time per day）,and treatment group 2（electro-acupuncture on acupoints of Baihui and Dazhui,two times per day）.The effect of acupuncture at different doses on DG synaptic plasticity was observed.Results The input and output curve（I/O curve） amplitude of excitatory postsynaptic potential（EPSP） and population spike（PS） was decreased obviously in the model group（P〈0.05 compared with the pseudo-operation group）,increased in the treatment group 1（P〈0.05 vs the model group,P〉0.05 vs the pseudo-operation group）,and elevated in treatment group 2（P〈0.05 vs the model group）.I/O curve amplitude of EPSP was lowered in treatment group 2 as compared with the pseudo-operation group（P〈0.05）,but the difference of PS amplitude was insignificant（P〉0.05）.The I/O curve amplitude of EPSP was lowered in treatment group 1 as compared with the treatment group 2（P〈0.05）,but the difference of PS amplitude was insignificant（P〉0.05）.Long-term potentiation（LTP） amplitude of EPSP was increased in the model group and the treatment groups（P〈0.05 vs pseudo-operation group）,but the difference between the model group and the treatment groups was insignificant（P〉0.05）.LTP amplitude of PS was decreased in the model group（P〈0.05 vs pseudo-operation group）,and higher in the treatment groups than that in the model group（P〈0.05）,but the difference between the pseudo-operation group and the treatment groups was insignificant（P〉0.05）.Long-term depression（LTD） amplitude of EPSP was decreased in the model group and the treatment groups（P〈0.05 vs pseudo-operation group）,but the difference between the model group and the treatment groups was insignificant（P〉0.05）.The difference of LTD amplitude of PS was insignificant between the model group and the pseudo-operation（P〉0.05）.In treatment group 1,LTD amplitude of PS was increased（P〈0.05 vs the pseudo-operation group,P〉0.05 vs the model group）.The difference of LTD amplitude of PS between treatment group 2 and the other 3 groups was insignificant（P〉0.05）.Conclusion Acupuncture has an effect on I/O curve amplitude of EPSP and PS,and on LTP induction of PS of dentate gyrus（DG） in rats after cerebral ischemia.However,the difference of effect of acupuncture at different doses on LTP induction is insignificant.