迷走神经刺激对大鼠癫痫持续状态的影响

Effect of vagus nerve stimulation on status epilepticus in rats

目的在氯化锂-匹鲁卡品诱发大鼠癫痫持续状态（SE）模型中探讨迷走神经刺激（VNS）对SE的影响。方法48只Wistar雄性大鼠按照随机数字表法分为4组：A组（VNS预处理组），注射匹鲁卡品前2h开始VNS刺激；B组（VNS治疗组），注射匹鲁卡品后开始VNS刺激；C组r阴性对照组），行VNS电极植入但不予刺激；D组（模型对照组），不予VNS电极植入；每组12只。采用氯化锂-匹鲁卡品腹腔注射诱发大鼠SE。VNS参数：频率30Hz，波宽500μs，电流1mA，刺激时间30S，间隔30S。观察各组大鼠行为学改变，72h后脑组织切片检测各组海马齿状回Caspase-3表达变化。结果（1）A、B组大鼠Ⅳ、Ⅴ级（Racine分级）发作次数明显少于C、D组，A组V级发作次数明显少于B组，A组sE潜伏期较其他各组均延长，差异均有统计学意义（P〈0．05）。（2）A、B2组大鼠海马齿状回Caspase-3表达量明显低于C、D2组似值分别为5854．7±856．5、6244．8±806．0；11957．0±1948．1、11543．2±1734．7），差异有统计学意义衅0．05）。结论VNS能够使SE大鼠行为学得到改善。且VNS预处理效果优于治疗性VNS刺激；VNS能够减少SE导致的海马神经元早期凋亡，对海马神经元有保护作用。

Objective To study the acute effect of vagus nerve stimulation （VNS） on status epileptieus （SE） in rats. Methods Forty-eight male Wistar rats were randomly divided into 4 groups： Group A （VNS preconditioning group）, accepted VNS at 2 h before pilocarpine injection, Group B （VNS treatment group）, accepted VNS immediately after pilocarpine injection, Group C （negative control group）, implanted with electrode without stimulation, and Group D （SE model group）, without electrode implantation （n=12）. Lithium-pilocarpine was used to kindle the rats to establish SE models. Stimulation parameters used in the procedure of VNS were as follows： frequency, 30 Hz; pulse width, 0.5 ms; current, 1 mA; and duty cycle, on-30 s, off-30 s. Behavior changes were observed and caspase-3 expression in dentate gyrus was detected 72 h after pilocarpine injection. Results （1） The seizure frequencies of grade 1V and V （Racine grading） in group A and B were significantly fewer than those in group C and D （P〈0.05）; the seizure frequency of grade V in group A was significantly fewer than that of group B （P〈0.05）; SE latency in group A was significantly longer than that in other groups （P〈0.05）. （2） Expressions of caspase-3 in the dentate gyms of group A and B were significantly lower than those of group C and D （absorbancy values being 5854.7±856.5, 6244.8±806.0, 11957.0±1948.1 and 11543.2±1734.7,P〈0.05）. Conclusion VNS has an acute seizure-suppressing effect on SE in rats and it can also reduce neuronal apoptosis induced by SE in hipocampus.