脑皮质电刺激对癫痫大鼠脑皮质兴奋性的影响

The effects of electric cortical stimulation on the cortical excitability in the epileptic rats

目的 观察重复脑皮质电刺激对氯化铁诱发慢性癫痫大鼠模型脑皮质兴奋性的影响.方法 通过在运动感觉区脑皮质注射氯化铁建立慢性癫痫大鼠模型,给予脑皮质低频（1 Hz）低强度（0.1 mA）和低频（1 Hz）高强度（1.0 mA）、高频（100 Hz）低强度（0.1 mA）和高频（100 Hz）高强度（1.0 mA）不同的重复电刺激,检测电刺激前后脑皮质后放电阈值、后放电时程和行为学评分.假刺激慢性癫痫大鼠作为对照组.结果 后放电阈值低频低强度组（2.10±0.38）mA与对照组（1.50±0.33）mA相比差异有统计学意义（P＜0.05）.行为学评分和后放电时程各组与对照组相比差异无统计学意义.行为学评分与后放电阈值的比值低频低强度组（1.88±0.60）和低频高强度组（2.18±0.38）与对照组（3.22±0.67）相比差异有统计学意义（P＜0.01和P＜0.05）.结论 重复低频低强度脑皮质电刺激可以升高氯化铁诱发慢性癫痫大鼠模型的脑皮质后放电阈值,降低脑皮质兴奋性,提示合适参数的脑皮质电刺激对氯化铁诱发大鼠癜痫具有抑制作用.

Objective To study the effects of repetitive electric cortical stimulation on the cortical excitability in the chronic epileptic rats induced by ferric chloride. Methods The chronic epileptic rats induced by intracortical injection of ferric chloride solution in the sensorimotor area were used. So we studied the effects of the low frequency （1 Hz） low amplitude （0.1 mA）and low frequency （1 Hz）high amplitude （1.0 mA）and high frequency（100 Hz）low amplitude（0.1 mA）and high frequency（100 Hz）high amplitude（1.0 mA）electric cortical stimulation on the cortical excitability by investigated the threshold and duration of cortical after discharge and the behavior score in the chronic epileptic rat. At the same time rats were treated with the sham-stimulation as control group. Results After 1 Hz and 0.1 mA repetitive electric cortical stimulation in 5 d, the cortical afterdischarge threshold （2.10 ±0.38）mA significantly ascended compared with that of the control group （1.5 ±0.33） mA, P 〈 0.05. There was no statistic difference of behavior score and duration of cortical afterdischarge after repetitive electric cortical stimulation in 5 d compared with that of the control group. The ratio of behavior score and cortical afterdischarge threshold after 1 Hz and 0. 1 mA （1.88 ±0.60） or 1 Hz and 1.0 mA （2.18 ±0.38） repetitive electric cortical stimulation in 5 d was significantly lower than that of the control group （3.22 ±0.67, P 〈0.01 and P 〈0.05, respectively）. Conclusion After the repetitive low frequency（1 Hz）low amplitude （0.1 mA）electric cortical stimulation the cortical afterdischarge threshold significantly ascended in the chronic epileptic rat induced by intracortical injection of ferric chloride solution. It means the depression of cortical excitability. The results of this study showed that electric cortical stimulation with suitable parameter can produce a suppressive effect on the epileptic rat induced by intracortical injection of ferric chloride solution.