迷走神经刺激的启动时间对抗癫痫作用的影响

背景长期反复痫性发作可影响记忆功能以及发生许多意料不到的并发症.如何控制和预防其发作是临床和康复医学研究的重点.目的应用大鼠癫痫模型,探讨迷走神经刺激(vagus nerve stimulation.VNS)治疗癫痫的最佳启动时间.设计随机对照的实验研究.地点和对象实验地点首都医科大学神经生物学研究室.实验对象Wistar大鼠34只,二级,首都医科大学实验动物中心提供.方法应用海人酸(kainic acid,KA)复制大鼠癫痫模型,以大鼠皮质电图(electrocorticographic,ECoG)和行为学为观测指标,在癫痫发作前后分别刺激左侧迷走神经,比较两组迷走神经刺激不同的启动时间对癫痫发作持续时间的影响,确定迷走神经刺激输出的最佳时机.主要观察指标①海人酸诱发癫痫的潜伏期和持续期.②VNS的启动时间对控制癫痫发作的影响.结果在癫痫发作前,间断刺激迷走神经50 min,可显著降低癫痫发作的严重程度、缩短发作的持续时间,甚至完全抑制癫痫发作.而发作一旦发生再行该组合刺激,则只能降低发作的严重程度、缩短发作的持续期,而不能完全阻抑癫痫发作.发作前后进行迷走神经刺激的抗痫效果之间存在显著性差异(F=27.320,P＜0.01).结论在癫痫发作前及时启动VNS可以显著提高VNS的抗痫效果,适宜的刺激参数组合是控制癫痫发作的关键,并为其预防发作奠定实验基础.

Effects of vagus nerve stimulation at different output time on seizures in rats

BACKGROUND:Repeated long-term seizures can impact on the function of memory and cause some unexpected complications. It is the study focus of clinic and rehabilitative medicine how to control and prevent its onset.OBJECTIVE: To probe into the most appropriate output time of vagus nerve stimulation(VNS) for treating seizure with the epileptic model of rat.DESIGN: A randomized and controlled study.SETTING and MATERIALS: The experiment was completed in the Department of Neurobiology, Capital University of Medical Sciences; Thirty-four Wistar rats, grade of cleanness, second degree, were supplied by the center of Experiment Animals Science, Capital University of Medical Science.METHODS: Epileptic model was prepared with Kainic Acid(KA) . The changes of eleetrocortieogram(ECoG) and behavior were observed by stimulating the left vagus nerve before or after the onset of seizures respectively. The seizure duration of two groups was compared to determine the most appropriate stimulus output time.MAIN OUTCOME MEASURES: ① The latent period and seizure duration induced by KA. ② Effect of stimulus output time of VNS on controlling the seizure.RESULTS: The intensity and duration of epileptic seizures were strikingly decreased or even aborted completely with VNS, stimulating 50 minutes before the onset of seizures. VNS shortened but did not shut down the seizure once it had begun. There was a significant difference between antiepileptic effects of VNS before or after the onset of seizures ( F = 27. 320, P ＜ 0. 01).CONCLUSION: The effects of stimulating the vagus nerve depend on the output time of VNS; the most effective method for preventing epilepsy is to stimulate vagus nerve before the onset of seizures . The method may provide an experimental basis for preventing the onset of seizure.