不同频率重复经颅磁刺激对脊髓损伤大鼠运动功能的影响

Effects of repetitive transcranial magnetic stimulation of different frequencies on motor function of rats with spinal cord injury

目的:研究不同频率重复经颅磁刺激(rTMS)对不完全性脊髓损伤(SCI)大鼠运动功能的影响。方法:65只SD雌性大鼠随机分为正常组、模型组、磁刺激5Hz组、10Hz组和20Hz组,每组13只。用Allen重物坠落法将模型组和磁刺激组制作成不完全性脊髓损伤模型。术后24h开始对磁刺激组实施rTMS治疗,刺激频率分别为5Hz、10Hz、20Hz,刺激强度均为90%运动阈值,刺激5s,间歇10s,共500个脉冲。每天1次,每周5d,连续4周,对照组不给予刺激。于术后第4周分别给予BBB行为学评分;检测运动诱发电位(MEP),记录潜伏时及波幅;并应用免疫组织化学法和Western blot法检测脊髓损伤处生长相关蛋白43(GAP-43)的表达情况。结果:BBB评分结果显示20Hz组大鼠分值最高,10Hz组次之,两者与模型组比较差异均有显著性意义(P<0.01);10Hz组大鼠的MEP潜伏时最短,20Hz组次之,两者与模型组比较差异有显著性意义(P<0.01);免疫组织化学及Western blot结果均显示10Hz组GAP-43表达量最高,20Hz组次之,两组与模型组比较差异均有显著性意义(P<0.01,P<0.05)。结论:高频rTMS可促进不完全性脊髓损伤大鼠运动功能恢复,以10Hz频率为佳。

Objective：To investigate the effects of repetitive transcranial magnetic stimulation（rTMS） of different frequencies on motor function of rats with incomplete spinal cord injury（SCI）. Method： Sixty-five rats were randomly divided into normal, control, rTMS 5Hz,10Hz and 20Hz groups,with 13 rats in every group.SCI models were induced by Allens weight-drop device. rTMS group received rTMS treatment once daily, 5d/week for consecutive 4 weeks. The 5s bursts of 5Hz/10Hz/20Hz at 90% motor threshold were used with each burst being separated by 10s interval. The control group received no stimulation. The scores of Basso,Beattie,Bresnahan（BBB） scale and amplitude as well as latency of motor evoked potential（MEP） were recorded after 4 weeks. At the same time,the immunohistochemistry and Western blot technique were applied to determine the expression level of growth associated protein-43（GAP-43） in spinal cord. Result：The BBB scores revealed the 20Hz group got the highest score,the 10Hz group was the second,and the diversity with control group was significant（P〈0.01）; the 10Hz group got the shortest latency of MEP,the 20Hz group was the second, and the diversity of latency with control group was significant（P〈0.01）. The immunohistochemistry and Western blot results all revealed the 10Hz group got the highest expression level,the 20Hz group was the second,both were statistically higher than those in control group（P〈0.01,P〈0.05）. Conclusion：rTMS of high frequencies could enhance the motor function of incomplete spinal cord injury rats,and the optimal frequency is 10Hz.