Establishment of animal model of refractory epilepsy and preliminary study of the effects of vagus nerve stimulation on electroencephalogram in this model

Abstract

Objective To establish the refractory epilepsy (RE) rat model and study the effects of vagus nerve stimulation on electroencephalogram (EEG) in RE rats.Methods Based on the Lithium-Pilocarpine induced temporal lobe epilepsy model,screening out the anti-PB epileptic rats by Sodium Phenobarbital (PB).The rats were randomly divided into 3 groups:VNS group,sham-VNS group and control group.The parameters of the VNS were set as follows:frequency 30 Hz,pluse width 0.5 ms,current 1 mA,stimulation time 30s,interval 5 min,10 hours/day.Behavior and EEG were observed by Video-EEG systerm before and after four-week VNS in each group.Results (1) The frequency of seizures in VNS group was significantly reduced after 4-week VNS (P ＜ 0.05),but that of group sham-VNS and group control did not change significantly.(2) The indexs of group VNS,including the duration of seizures,the spike numbers and spike interval,were significantly reduced after 4-week VNS (P ＜ 0.05),however the sham-VNS and EP control groups did not change significantly.(3)The spectrogram showed cpileptiform-wave frequency of epileptic rat reduced after 4-week VNS,but the maximum energy value did not change obviously,though it was higher than that of normal rats with the same age.Conclusions The RE rat could be screened out by PB on the basis of TLE cpilepsy model.VNS could efficiently decrease the frequency of seizures,especially change the EEG pattern. Key words: Temporal lobe epilepsy ; Refractory epilepsy ; Vagus nerve stimulation ; Electroencephalogram ; Models animal