目的:观察不同刺激强度的高频重复经颅磁刺激(rTMS)对脑梗死大鼠运动诱发电位(MEP)的影响.方法:43只大鼠随机分为正常组、模型组、假刺激组、rTMS组(按不同刺激强度分80％ MT亚组、100％ MT亚组、120％ MT亚组).测定运动阈值(MT)后制备大脑中动脉栓塞模型.模型成功24h后给予20Hz,刺激时间2s,间隔时间28s,总脉冲数为1200的rTMS刺激,连续刺激14d.观察术前、术后1d、治疗7d和治疗14d时双侧中枢传导时间(CMCT)和皮质潜伏时(CL)的变化.结果:①术前各组左右侧CMCT、CL的比较差异均无显著性意义(P＞0.05).②术后1d左侧CMCT、CL较术前和右侧缩短(P＜0.01).③治疗7d时,双侧CMCT、CL各组之间以及各组双侧CMCT、CL比较差异均无显著性意义(P＞0.05).④治疗14d时,100％ MT亚组左侧CMCT、CL较正常组和治疗7d时均缩短(P＜0.05),双侧CMCT、CL均较术前缩短(左侧P＜0.01,右侧P＜0.05)；80％ MT亚组右侧CMCT、CL较术后1d缩短(p＜0.05).结论:本实验结果提示20Hz rTMS有助于促进脑梗死大鼠双侧CMCT和CL缩短使双侧大脑达到某种平衡或者代偿,80％ MT和100％ MT两种强度的rTMS作用可能较大.%Objective: To investigate the effects of high-frequency repetitive transcranial magnetic stimulation (rTMS) with different intensities on motor evoked potential(MEP) of rats with cerebral infarction.Method: A total of 43 rats were randomly divided into blank control group, model control group, sham stimulation control group, rTMS group which was divided into 3 subgroups, 80% MT subgroup, 100% MT subgroup and 120% MT subgroup. Resting motor threshold(MT) was determined, then the middle cerebral artery occlusion (MCAO) model was established. After the model was made successfully 24 hours, consecutive blocks of rTMS were given at 20Hz with 2s duration, 28s interval and 1200 total number of pulses for 14d. The central motor conduction time(CMCT) and cortical latency(CL) were detected at different time points, before MCAO operation, and Id after operation, after 7d rTMS and after 14d rTMS.Result: Before MCAO operation, CMCT and CL between both sides had no significant difference in each group (P>0.05). At the 1st d after operation, both CMCT and CL on the left side reduced significantly as compared with those on the right side and that before operation (P<0.01). After 7d rTMS, CMCT and CL on both sides hadon difference between the groups, each group also had no difference between both sides (P>0.05). After 14rl rTMS, CMCT and CL on the left side reduced as compared with those in blank rontrol group and those after 7d rTMS in 100% MT subgroup (P<0.05). CMCT and CL on both sides also reduced as compared with those before operation (left P<0.0I and light P<0.05). CMCT and CL on the righl side reduced as compared with those at the Ist d after operation in 80% MT Rul>grnup(P<0.05).Conclusion: IM'MS of 20Hz might promote the reducing of CMCT and CL. As well as the balance of both side hemispheres or evoke the unaffected hemisphere to compensate the functional impairments of affected hemisphere through decreasing CMCT and Cl, on boLh sides.RTMS of 80% MT and 100% MT seemed to have the best effect.
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