利多卡因惊厥对大鼠空间学习能力的影响

目的研究利多卡因对海马的神经毒性是否会对大鼠空间学习记忆能力产生影响,并探讨大鼠空间学习能力的变化与海马CA3区锥体细胞数目的相关性。方法将成年Wistar雄性大鼠随机分为基础值组(n=7)和利多卡因惊厥组(n=40)。基础值组大鼠静脉给予生理盐水后使用Y迷宫测定大鼠的空间学习能力。利多卡因惊厥组大鼠尾静脉持续输注利多卡因造成惊厥,待大鼠恢复正常运动以后放入鼠笼重新饲养。并于惊厥后第1、3、5、7天从中随机抓取大鼠测试其空间学习能力以及组织学改变。根据对应天数将利多卡因惊厥组的40只大鼠随机细分为Day-1、Day-3、Day-5、Day-7亚组,每亚组10只。所有大鼠在测定空间学习能力之后立即处死,取出大脑并做石蜡包埋,冠状面切片后进行组织学检测,显微镜下评估海马CA3区锥体细胞状态。结果①基础值组和Day-1、Day-3、Day-5、Day-7亚组大鼠的Y迷宫穿梭次数分别为(25.2±3.7)、(27.1±8.1)、(36.9±9.9)、(38.7±10.6)、(40.6±16.3)次,除Day-1亚组与基础值组比较差异无统计学意义(P>0.05)外,其余各亚组与基础值组差异均有统计学意义(P<0.05);②与基础值组单位面积(10.3±4.5)个(异常锥体)细胞比较,利多卡因惊厥组大鼠海马CA3区异常锥体细胞数增加,Day-1、Day-3、Day-5、Day-7亚组计数值分别为13.0±7.2、15.6±5.0、19.6±8.1、18.1±5.1,且与大鼠Y迷宫穿梭次数呈正相关(r=0.711,P<0.05)。结论利多卡因引起的惊厥使成年大鼠海马依赖性空间学习能力下降,利多卡因的神经毒性引起的海马异常锥体细胞增多可能是造成这一现象的一种原因。

Effect of Lidocaine-induced Seizure on Spatial Learning Memory in Rats

Objective To investigate whether the neuronal damage in the CA3 hippocampus could induce spatial learning dysfunction in rats,and to explore possible correlation between the number of pyramidal neuron in CA3 area and the ability of spatial learning memory.Methods Several Wistar rats were randomly assigned to baseline group(n=7) and lidocaine seizure group(n=40).Baseline group received intravenous injection with saline and lidocaine seizure group received continuous infusion of lidocaine until the presence of seizure.Then the spatial learning memory of rats was evaluated by Y maze.Rats of baseline group were evaluated right after intravenous injection with saline while lidocaine seizure group were tested at day 1,3,5,and 7 after lidocaine induced seizure which was divided into four subgroups named as group day-1,day-3,day-5,and day-7.All of rats were sacrificed when they had completed the Y maze test.The brains of the rats were removed and were embedded in paraffin immediately.Coronal cuts were made and each brain section was stained in order evaluated the number of normal and abnormal pyramidal cells in the hippocampal CA3.Result 1.Compare to the baseline group(25.25 ± 3.69),the number of accomplishment of Y maze was 27.1±8.12,36.9 ± 9.94,38.7 ± 10.56,and 40.6 ± 16.31 in group day-1,day-3,day-5,and day-7,respectively.The difference between each subgroup and baseline group was significant(P<0.05) except for group day-1(P>0.05).2.Compare to the baseline group(10.31 ± 4.51),the numbers of abnormal neurons in the hippocampal CA3 increased in lidocaine seizure group:13.0 ± 7.24,15.58 ± 4.96,19.56 ± 8.11,and 18.1 ± 5.1 in group day-1,day-3,day-5,and day-7,respectively,which expressed a positive correlation with the number of accomplishment of Y maze(r=0.711,P<0.05).Conclusion Lidocaine-induced seizure may reduce hippocampal dependent spatial learning memory which may probably attribute to the increase of abnormal pyramidal neurons caused by lidocaine.