重复经颅磁刺激对急性脊髓损伤大鼠运动功能的影响

目的 探讨重复经颅磁刺激对急性脊髓损伤大鼠运动功能的影响. 方法 24只SD大鼠按照随机数字表法分为正常组、脊髓损伤对照组(对照组)、脊髓损伤高频磁刺激组(高频组)、脊髓损伤低频磁刺激组(低频组),每组6只.利用重物撞击法制作T10脊髓损伤模型.磁刺激组于手术后24 h开始给予刺激,高频组频率为10Hz,低频组频率为1 Hz,均为阈值刺激.500个脉冲,每天1次,连续4周,脊髓损伤对照组给予假刺激.各组大鼠分别于术后1 d、3d、7d、11 d、14d、21 d、28 d进行BBB行为学评分,于14、28 d时检测运动诱发电位(MEP),应用HE染色观察脊髓组织形态学变化,并应用免疫组织化学法检测神经丝蛋白(NF-200)表达变化. 结果 高频组、低频组大鼠BBB评分明显高于对照组,高频组BBB评分明显高于低频组,差异均有统计学意义(P<0.05).高频组、低频组运动诱发电位潜伏期较短,与对照组、正常组相比差异均有统计学意义(P<0.05);其中高频组较低频组短,差异有统计学意义(P<0.05).高频组、低频组NF-200表达较对照组明显升高,差异均有统计学意义(P<0.05);其中高频组较低频组高,差异有统计学意义(P<0.05).结论 重复经颅磁刺激可以促进脊髓损伤大鼠运动功能的恢复,其机制可能与促进轴突再生有关.高频组较低频组效果明显可能与调节大脑皮层兴奋性有关.

Effects of repetitive transcraniai magnetic stimulation on motor function of rats with acute spinal cord injury

Objective To investigate the effects of repetitive transcraniai magnetic stimulation (rTMS) on rats with acute spinal cord injury (SCI). Methods Twenty-four SD rats were equally randomized into normal group, SCI control group, high-frequency rTMS group and low-frequency rTMS group (n=6). T10 spinal cord injury models were induced by weight-drop device. Twenty- four h after the success of model making, high-frequency rTMS group received 10 Hz threshold rTMS and low-frequency rTMS group received 1 Hz threshold rTMS once daily for a consecutive 4 w. SCI control group received sham stimulation. The scores of Basso Beatti and Bresnahan (BBB) locomotor rating scale were recorded 1, 3, 7,11, 14, 21 and 28 d after the success of model making. Motor evoked potential (MEP) was detected on the 14th and 28th d of injury. HE staining was employed to detect the changes of histomorphology and neurofilament (NF-200) protein was detected with immunofluorescence staining in the spinal cord injury lesion. Results The BBB scores in stimulation groups were significantly higher as compared with those in the SCI control groups (P<0.05); those in the high-frequency rTMS group were statistically higher than those in the low-frequency rTMS group(P<0.05). The MEP was shorter in the stimulation groups as compared with that in the other 2 groups (P0.05); that in the high-frequency rTMS group was statistically shorter than that in the low-frequency rTMS group (P<0.05). NF-200markers in the stimulation groups were significantly increased compared with those in the SCI control group (P<0.05); those in the high-frequency rTMS group were statistically higher than those in the low-frequency rTMS group (F<0.05). Conclusion The rTMS can improve the locomotor function of rats with spinal cord injury, resulting from the increased expression of NF-200. The obvious effects in the high-frequency rTMS group might relate to the regulation of cortex excitability.