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。
ObjectiveTo investigate the neuroprotective effects and mechanisms of selective histone deacetylases inhibitor MS-275 on rats after seizures. MethodsA total of 75 rats were randomly divided into 5 groups for treatment:control group,pilocarpine group, treatment group Ⅰ(administered with MS-275, 20mg/kg, once a day,intraperitoneally in 7 consecutive days), treatment group Ⅱ(administered with MS-275, 40mg/kg, once a day, intraperitoneally in 7 consecutive days), MS-275 pretreatment group. We used lithium and pilocarpin to induce seizures. Behaviors of rats in each group were observed. At 72 hours after seizures, Nissl staining and immunohistochemical were respectively used to evaluate the loss of neurons and histone acetylation levels of hippocampal CA1 and CA3 regions in each group. Escape latency in the control group, treatment group Ⅰ, treatment group Ⅱ and MS-275 pretreatment group were longer than pilocarpine group(P<0.05). ResultsCompared with the pilocarpine group, rats in MS-275 pretreatment group could delay pilocarpine-induced seizures and reduce mortality (P<0.05). Degree of neuronal loss and degeneration in both treatment group Ⅰ and treatment group Ⅱ were reduced compared with the pilocarpine group (P<0.05) and the level of histone acetylation in hippocampal CA1 and CA3 regions of the rats were increased compared with the pilocarpine group (P<0.05). ConclusionHDACs inhibitors MS-275 can improve the neuronal damage, histone deacetylation of rats' brain and rats cognitive decline, which can exert an neuroprotective effect on rats after seizures, whose mechanism may be related to its antiinflammatory effect.
ObjectiveTo investigate the effects of hippocampal long-term potentiation (LTP) on cognitive dysfunction in immature epileptic rats. MethodsImmature epileptic rats were established by intraperitoneal injection of lithium chloride-pilocarpine (li-pilo). Racine classification standard modified by Becker was used to evaluate behavior of epileptic seizure, and the survival rats within RacineⅣmagnitude were selected in the experiment. The function of learning and memory of epileptic rats when they were adult was assessed using Morris water maze experiment, and their independent exploratory behavior was evaluated by the open-field test. Field potential was recorded by electrophysiological technology to detecte whether hippocampal LTP was essential of cognitive dysfunction. ResultsThe function of learning and memory was significantly impaired when compared with controls(n=8, t=10.86, P < 0.05;n=8, t=9.98, P < 0.05). In addition, independent exploratory behavior was significantly reduced when compared with controls(n=8, t=12.89, P < 0.05). Besides, CA1 hippocampal LTP induced by high-frequency stimulation presented the significant inhibition in epileptic rats with cognitive dysfunction when compared with controls(Slope:n=8, t=13.32, P < 0.05;Amplitude:n=8, t=20.02, P < 0.05). ConclusionInhibition of CA1 hippocampal LTP may be implicated in cognitive dysfunction of epileptic rats.
ObjectiveTo explore the dynamic expression changes of neuronal growth and differentiation-associated miR-124a and miR-9 in the process of epileptogenesis. MethodsEstablish the lithium-pilocarpine induced status epilepticus (SE) rat model. Animal behavior change induced by SE as well as in the period of chronic epilepsy was observed by naked-eye or video-recording. Major time points for the study were chosen at 1d, 7d, 14d and 28d post-SE, on which the post-SE rats were decapitated and their hippocampal specimens were obtained. Total RNA from each specimen was extracted and qPCR was exploited to detect miR-124a and miR-9 expression in the specimens. Statistical analysis was used to show the dynamic expressional changes of miR-124a and miR-9 in rat hippocampus at 1d, 7d, 14d and 28d post-SE during the process of epileptogenesis. ResultsCompared with normal rats, the expression level of miR-124a in rat hippocampus did not show a significant difference at 1d post-SE, but it had shown markedly differences at 7d, 14d and 28d post-SE(P < 0.05), with a declining trend. Compared with normal rats, the expression level of miR-9 had demonstrated significant differences at 1d, 7d, 14d and 28d post-SE(P < 0.05)with a generally increasing trend, although there was slight fluctuation of expressional up-regulation at 7d post-SE. ConclusionNeuronal growth and differentiation-associated miR-124a and miR-9 had shown dynamic changes of down-regulation or up-regulation in the process of epileptogenesis. It can be suspected that miR-124a and miR-9 take part in hippocampal neurogenesis post-SE and be involved in epileptogenesis process.
ObjectiveTo determine the outcome of antiepileptic drugs (AEDs) withdrawal in patients who had been seizure-free for more than two years. MethodsPatients with epilepsy who had been seizure-free for at least two years and decided to stop AEDs therapy gradually were checked on every two months for seizure relapse. The inclusion criteria were:①diagnosis of epilepsy, defined as at least two unprovoked seizures at least 24 hours apart; ②patients remained seizure-free for at least 24 consecutive months during AEDs therapy; ③patients expressed a desire to discontinue AEDs therapy gradually and agreed to return for regular follow-ups; and④electroencephalogram (EEG) showed no epileptic discharge. The time to a seizure relapse and predictive factors were analyzed by survival methods, including sex; age at seizure onset; number of episodes; seizure-free period before AEDs withdrawal; duration of follow-up after AEDs withdrawal; AEDs tapering off period (taper period); results from brain MRI; EEG before seizure-free; EEG before drug withdrawal; seizure type (classified as generalized, partial, or multiple types based on history); the number of AEDs administered for long-term seizure control. A log-rank test was used for univariate analysis, and a Cox proportional hazard model was used for multivariate analysis. ResultsSixty-eight patients (39 male, 29 female) were admithed. The relapsed rate was 23.5%. Univariate analysis and multivariate Cox regression analysis indicated that multiple AEDs, hippocampal sclerosis and withdrawal time were significantly correlated with seizure recurrence and those were significant independent predictive factors, with hazard ratio were 0.861, 2.223 and 2.137 respectively. ConclusionsThe relapsed rate in our study was similar to other studies. Distinguishing variables, such as multiple AEDs, hippocampal sclerosis and withdrawal time, need to be considered when decide to withdraw. Therefore, our recommendation is that after two years of being seizure-free, patients could consider withdrawal unless they are hippocampal sclerosis patients.