跑台训练对脑梗死大鼠海马5-HT、5-HT1A受体及突触素的影响

Effects of treadmill exercises on 5-HT，5-HT1A receptor and synaptophysin in the hippocampus of rats after cerebral infarction

摘要:

目的：探讨脑梗死后跑台训练对神经功能评分及大鼠缺血侧海马５-羟色胺（5-hydroxytryptamine，5-HT）含量、5-HT1A受体及突触素表达的影响。方法：采用SD大鼠60只，随机分为模型组、运动训练组及假手术组，每组各20只。采用大脑中动脉闭塞（middle cerebral artery occlusion，MCAO）方法造成局灶性脑梗死模型。训练组于造模后第3天进行16 d的跑台训练。运用改良神经功能缺损程度评分（modified neurological severity scores，mNSS）对模型组及运动训练组进行神经功能评分。采用HE染色及尼氏染色观察各组海马CA2区神经细胞形态。高效液相色谱-电化学法检测海马组织5-HT含量。运用Western blot检测各组海马5-HT1A受体及突触素的蛋白水平，逆转录PCR方法检测5-HT1A受体mRNA水平变化。结果：MCAO术后19 d，运动训练组mNSS评分较模型组明显改善（P＜0.001）。HE染色及尼氏染色显示假手术组中海马CA2区细胞形态完整；模型组细胞形态不规则，细胞受损明显；运动训练组细胞受损减轻。运动锻炼组5-HT含量（14.5±1.71） ng/ml较模型组（7.13±0.71） ng/ml有明显增高（P<0.001）。运动训练组5-HT1A受体蛋白及mRNA表达水平较模型组明显增加（P＜0.05），突触素蛋白表达在运动训练组也较模型组明显增加（P＜0.05）。结论：跑台训练可改善局灶性脑梗死大鼠神经功能评分，增加海马组织5-HT含量及5-HT1A受体表达，提高突触可塑性。

Abstract:

Objective：To discuss the effects of treadmill exercises on scores of neurological function，contents of 5-hydroxytryptamine（5-HT） and expressions of 5-HT1A receptor and synaptophysin in the hippocampus of rats after cerebral infarction. Methods：A to－tal of 60 rats were randomly divided into three groups：permanent middle cerebral artery occlusion（pMCAO） group（n=20），pMCAO and treadmill exercise（pMCAO+Ex） group（n=20） and sham-operated group（n=20）. Middle cerebral artery occlusion（MCAO） method was used to establish focal cerebral infarction model. Rats in pMCAO+Ex group underwent treadmill exercise on the 3rd d after model establishment for 16 d. Neurological function was evaluated using modified neurological severity scores（mNSS）. HE stain－ing and nissel staining were used to observe neuron damages in CA2 region. High performance liquid chromatography-electrochemi－cal detection system was used to determine levels of 5-HT in ischemia hippocampus tissues. Protein levels of 5-HT1A receptor and synaptophysin were measured by Western blot and mRNA levels of 5-HT1A receptor were determined by reverse transcription- poly－merase chain reaction. Results：mNSS was lower in pMCAO+Ex group than in pMCAO group on the 19th d post MCAO（P<0.001）. Both stainings showed that the morphologies of neurons in CA2 region were normal in sham-operated group and irregular in pMCAO group with parts of neurons being obviously damaged；after treadmill exercise，the damage was alleviated. Contents of 5-HT was higher in pMCAO+Ex group（14.5±1.71） ng/ml than in pMCAO group（7.13±0.71） ng/ml（P<0.001）. Protein and mRNA expres－sions of 5-HT1A receptor and protein expressions of synaptophysin were upregulated after treadmill exercise compared with those in pMCAO group（P<0.05）. Conclusions：Treadmill exercises could improve neurological function and increase contents of 5-HT and levels of 5-HT1A receptor in the hippocampus to improve synaptic plasticity.