Effects Of Repetitive Transcranial Magnetic Stimulation On The Motor Function Recovery Of The Cerebral Infarction Rats

Cerebral infarction is a kind of diseases with high mortality and mutilation. After cerebral infarction,a large number of patients survive with disabilities,which is mainly motor function defect.Thus,to develop a new effective and feasible therapy of rehabilitation is an important content of neurological research.In this study,96 adult male SD rats were divided randomly into four groups, which were the model group,sham stimulation group,acute low-frequency repetitive transcranial magnetic stimulation(rTMS)group and chronic low-frequency rTMS group.Each Group was divided into three time points with 8 rats:the 6^thday,13^th day,and 27^thday after cerebral ischemia-reperfusion.The right middle cerebral artery occlusion(MCAO)of cerebral ischemia-reperfusion model was prepared by a thread, then the rats were treated with rTMS.An 18-score scale was performed to evaluate the neurological deficits,and electron microscopy was used to observe synaptic damage at the side of the cortex infarction of cerebral ischemia-reperfusion after 27d, in order to find the effects of the rTMS for the restoration of nerve function and cerebral cortex plasticity of the cerebral infarction rats.In the same time,the application of immunohistochemistry detected the expression of brain-derived neurotrophic factor(BDNF),vascular endothelial growth factor(VEGF)and synaptophysin(SYN)in the ischemic cortex,to explore the possible mechanisms of changing neurological function and cortex plasticity.The aim is providing experimental basis for rTMS to be widely used in clinical treatment of patients with cerebral infarction rehabilitation in the future.The results show that:(1)in the 6th day after cerebral ischemia-reperfusion,the nerve dysfunction score of the acute low-frequency rTMS group was more than that of model group;in the 13^thday after cerebral ischemia-reperfusion,the nerve dysfunction scores of the acute low-frequency rTMS group and the chronic low-frequency rTMS were more than that of model group;in the 27^thday after cerebral ischemia-reperfusion,there was no significant difference among the model group,sham stimulation group,acute and chronic low-frequency rTMS group in nerve dysfunction score;while there was no significant difference of nerve dysfunction score between acute and chronic low-frequency rTMS group in the 13^th day and 27^thday after cerebral ischemia-reperfusion;(2)the number of BDNF positive cells,VEGF positive ceils and SYN-positive cells in ischemic cortex of acute low-frequency rTMS group was more than that of the model group in three time points;in the 27^thday after cerebral ischemia-reperfusion,the number of BDNF positive cells,VEGF positive cells and SYN-positive cells in ischemic cortex of chronic low-frequency rTMS group was more than that of the model group;while there was no significant difference of the number of BDNF positive cells,VEGF positive cells and SYN-positive cells in ischemic cortex between acute and chronic low-frequency rTMS group in the 13^thday and 27th day after cerebral ischemiareperfusion;(3) according to the electron microscope specimens,the damage extent of synapses of the ischemic cortex in acute and chronic low-frequency rTMS group in the 27^thday after cerebral ischemia-reperfusion was relatively lighter,compared with that of model group and sham stimulation group.The preliminary conclusions of this study are as follows:(1)rTMS plays a certain role in promoting restoration of nerve function in rat with cerebral ischemia-reperfusion injury,especially in the 6^thday and 13^thday after cerebral ischemia-reperfusion.(2)The number of BDNF positive cells and VEGF positive cells of ischemic cortex in rat with cerebral ischemia-reperfusion injury increases,and significantly in the 6^thday after cerebral ischemia-reperfusion,then gradually falls. The number of ischemic cortex in rat with cerebral ischemia-reperfusion injury increases,and continues to the 27^thday.rTMS have different roles in promoting the increasing of the number of BDNF positive cells,VEGF positive cells and SYN positive cells ofischemic cortex in rat with cerebral ischemia-reperfusion injury.(3) We haven't yet found that there is obvious difference in the process of rehabilitation of motor function between acute and chronic low-frequency rTMS group.