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

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.