重复经颅磁刺激对帕金森病模型大鼠运动皮质兴奋性的影响

EFFECT OF REPETITIVE TRANSCRANIAL MAGNETIC STIMULATION ON THE EXCITABILITY OF MOTOR CORTEX IN RAT MODEL OF PARKINSON'S DISEASE

目的探讨0.5Hz重复经颅磁刺激对帕金森病大鼠运动皮质兴奋性的影响。方法取健康SD大鼠45只,用6-羟多巴毁损右侧黑质致密部(substantia nigra pars compacta,SNc)与中脑腹侧背盖(ventral tegmentalarea,VTA)制备偏侧帕金森病模型。用阿朴吗啡腹腔注射筛选,将成功的20只帕金森病鼠随机分为治疗组和对照组,每组10只。治疗组给予频率为0.5Hz,刺激强度为阈上30%,连续20个刺激,1次/d,连续2周的磁刺激。对照组予以假刺激。在治疗前、治疗结束后第1、14、28天分别进行运动诱发电位检测,观察皮质静息阈值的变化。结果治疗前右侧皮质静息阈值治疗组32.1±6.3和对照组31.9±6.2,差异无统计学意义(P>0.05);治疗组及对照组自身左右侧比较差异有统计学意义(P<0.05)。在治疗结束后第28天时,右侧阈值对照组29.1±5.7较治疗组34.0±3.2低,差异有统计学意义(P<0.05)。结论①毁损侧皮质兴奋性增高;②0.5Hz、阈上30%刺激强度的经颅磁刺激可抑制毁损侧皮质阈值下降,降低皮质兴奋性。

Objective To study the effect of 0.5 Hz repetitive transcranial magnetic stimulation(rTMS) on the excitability of motor cortex in the rat parkinson's disease(PD) model. Methods Fourty five SD rats were injected 6-hydroxydopamine(6-OHDA) in the right substantia nigra pars compacta(SNc) and ventral tegmental area (VTA),then the rotated rats were selected after injected apomorphine (APO) intraperitoneally as a successful PD model and divided into control and treatment groups randomly,10 rats in each group.The treatment group received transcranial magnetic stimulation once a day,the intensity was 30% over threshold,the frequency was 0.5 Hz,20 stimulates successively,2 weeks duration.While the control group was given false stimulation.The changes of relaxed threshold(RT) and the motor evoked potential were analysed before treated and on the 1st,14th and 28th day after treatment in two groups.Results There was no statistical significant difference in the diversity of the RT of the right cortex between the treatment group 32.1 ± 6.3 and the control group 31.9±6.2 before treatment(P >0,05).There were significant difference ( P <0.05) compared right and left side of a rat in two groups.The RT of the right side cortex of the treatment group 34.0±3.2 was higher than that of the control group 29.1 ± 5.7 on the 28th after treatment (P <0.05).Conclusion ①The excitability of cortex was increased in the injected SNc and VTA side; ②The stimulation,whose intensity was 30% over threshold,and frequency was 0.5 Hz,could restrain the drop of the RT of the destroyed side and decrease the excitability of cortex.