植入式迷走神经刺激器对红藻氨酸诱导兔癫痫模型的影响

Effect of Implantable Vagus Nerve Stimulator on Epilepsy Models Induced by Kainic Acid in Rabbit

目的研究植入式迷走神经刺激器（VNS）对实验兔癫痫模型的影响。方法实验兔大脑皮层下注射红藻氨酸，诱导癫痫模型。将螺旋电极安装在实验兔迷走神经上，VNS植入左侧背部皮下。将18只实验兔随机分为3组，A组（n=6）仅造模，假手术不植入VNS；B组（n=6）和C组（n=6）在安装VNS1周后进行如下操作：B组在造模前2h开启迷走神经刺激；C组造模后立即开启刺激。分别观察以上3组兔临床反应及脑电波，最后病理学观察VNS与相邻肌肉的生物相容性。结果癫痫模型诱导成功，癫痫临床表现明显；VNS植入后实验兔存活率100％，未见明显异常。B组癫痫波减少，脑电图逐渐平稳，癫痫临床表现缓解；而C组癫痫症状有一定改善，病理学观察未见VNS相邻的肌肉组织异常。结论植入式VNS对实验兔癫痫模型具有一定的干预效果，且提前开启迷走神经刺激效果较好，植入式VNS生物相容性良好。

Objective To study the intervention effect of implantable vagus nerve-stimulator （VNS） on epileptic rabbit model induced by kainic acid （KA）. Methods The epileptic model of adult rabbit was established through the micro-injection of kainic acid into the cerebral cortex of animal. To relieve the epilepsy by VNS, the spiral electrode was placed on the vagus nerve, while the stimulator was implanted in subcutaneous tissue of the left animal back. Then 18 rabbits were randomly divided into 3 groups including epilepsy model group （group A, n=6）, VNS pretreatment group （group B, n=6） and the VNS treatment group （group C, n=6）. In group A, none VNS was implanted in the epileptic animal. In group B and C, VNSs were implanted 7 days before the KA injection for the epilepsy induction. The electricity stimulation was performed 2 hours before epilepsy in group B. However, stimulation carried out immedi- ately when epilepsy emerges in group C. Epileptic behaviors and electroencephalography were observed and tested subsequently in all groups. The subcutaneous tissues around VNS were also observed via H. E stain to show the biocompatibility of VNS. Results All the animals showed stable epileptic seizure induced by KA and survived after the VNS plantation without obvious anomaly. The epileptiform electro- corticogram were ameliorated and the epileptic seizure remarkably suppressed in group B and were slightly restrained in group C. The tissues around the implanted VNS showed no obvious distinctions comparing with normal animal tissues in H.E stain. Conclusion VNS could alleviate the seizure of epileptic animal and show better effect when the vagus nerve is stimulated ahead of time. The implantable VNS is also biocompatible with animal subcutaneous tissues.