癫痫持续状态中海马神经元的保护:现状及展望

<正> 癫痫持续状态是神经系统常见的急危重症,持续的癫痫发作可导致脑损伤,其主要损伤部位在海马。因此,海马神经元保护成为延缓或逆转癫痫病理过程,改善患者预后的重要手段。电刺激海马或杏仁核可点燃癫痫,刺激小脑、迷走神经可埘抗癫痫发作,据此学者们推测机体内存在着一个在生物进化过程中逐渐形成的自我保护系统。癫痫发作引起脑细胞坏死的同时,也激活了这个系统以对抗痫性损伤。癫痫患者脑细胞损     

电针对实验性癫痫大鼠海马神经元发生的影响

目的研究电针对实验性癫痫(EP)大鼠海马神经元发生的影响,探讨针刺抗癫痫的机制,为临床实践服务。方法以锂-匹罗卡品制备癫痫模型,电针督脉穴位“大椎”与“百会”,采用疏密波,频率为80Hz,电流强度50mA,时间20min。在6d,13d,27d三个时间点分别腹腔注射2次BrdU,每次间隔2h。所有动物均在最后一次注射BrdU后的24h经左心室灌注处死。取脑后,将脑组织入4%多聚甲醛后固定过夜,再入20%蔗糖4℃冰箱沉底。选择海马部位应用恒冷冰冻切片机冠状位连续切片,脑片漂片厚30μm,行免疫细胞化学染色。结果从13d开始,与未经电针处理的EP鼠比较,经电针处理后的EP鼠海马BrdU阳性细胞数明显减少,且差别有显著性意义(P<0.05)。另外,两组间的反复自发性痫性发作(SRSS)次数亦有显著性差异(P<0.05),经电针处理的EP鼠SRSS次数减少。结论电针可减少SRSS次数并抑制神经元的发生。推测电针的抑痫作用是通过抑制SE后的SRSS而减少神经元的发生。     

从癫痫模型大鼠海马神经元中克隆caspase 3的新底物PIASI

目的 从癫痫模型大鼠海马凋亡神经元中克隆caspase-3的新底物。方法 制作癫痫模型大鼠海马组织cDNA文库；PCR获得caspase-3的P12和P17两亚基，然后分别定向插入pBridge质粒，构建三杂交诱饵栽体；进行酵母三杂交筛库。结果 建立成功癫痫模型大鼠海马组织cDNA文库，构建了大鼠caspase-3基因的酵母三杂交诱饵栽体，并通过了caspase-3与eIF2n之间的相互作用验证，筛库获得caspase-3的新底物PIASI。结论 用酵母三杂交系统寻找caspase-3下游底物具有可行性，从癫痫模型大鼠海马的cDNA文库中筛库获得caspase-3的新底物PIASl，为进一步研究caspase-3在癫痫发作引起的海马损伤中的作用奠定了基础。     

红藻氨酸致惊大鼠海马神经元Caspase—3表达与神经元凋亡

目的：研究Caspase-3在红藻氨酸（Kainate,KA)致惊大鼠海马中的变化及其在海马神经元凋亡中的作用。方法：在KA所致大鼠惊厥模型中，用免疫组织化学方法检测惊厥后不同时间点大鼠海马中Caspase-3的表达，用电子显微镜和原位末端标记法（TUNEL）检测惊厥后不同时间点大鼠海马神经元凋亡。结果：惊厥后1d,大鼠海马内Caspase-3的表达就明显升高，一直持续到惊厥3d；大鼠海马内凋亡细胞从惊厥后3d即明显增多，一直持续到惊厥后7d。结论：KA所致惊厥后，大鼠海马内Caspase-3表达明显升高，神经元凋亡明显增多，而且Caspase-3的变化发生在神经元亡增多之前，提示Caspase-3可能参与了KA致惊厥大鼠海马神经元凋亡的发生。     

下调GABA受体基因对癫痫模型大鼠海马神经细胞凋亡的影响及作用机制

目的 探讨下调GABA受体基因对癫痫模型大鼠海马神经细胞凋亡的影响及作用机制。方法 选择30只SD健康雄性大鼠,建立癫痫模型,建模成功后分为模型组、上调组、下调组各10只; 进行细胞转染建立稳定转染的GABA上调组、GABA下调组; 检测3组大鼠海马神经细胞凋亡及PI3K、AKt、mTOR、Bax、Caspase-3蛋白表达水平。结果 上调组大鼠各时间点海马神经细胞凋亡率高于模型组(P<0.05); 下调组大鼠各时间点海马神经细胞凋亡率低于模型组(P<0.05); 下调组大鼠各时间点海马神经细胞凋亡率低于上调组(P<0.05)。上调组大鼠各时间点海马神经细胞增殖率、Bcl-2、p-PI3K、p-AKt、p-mTOR蛋白表达水平均低于模型组,而Bax、Caspase-3蛋白表达水平高于模型组(P<0.05); 下调组大鼠各时间点海马神经细胞增殖率、Bcl-2、p-PI3K、p-AKt、p-mTOR蛋白表达水平均高于模型组,而Bax、Caspase-3蛋白表达水平低于模型组(P<0.05); 下调组大鼠各时间点海马神经细胞增值率、Bcl-2、p-PI3K、p-AKt、p-mTOR蛋白表达水平均高于上调组,而Bax、Caspase-3蛋白表达水平低于上调组(P<0.05)。结论 下调GABA受体基因可能是通过调节PI3K/AKt/mTOR来作用于下游凋亡靶基因,最终抑制癫痫模型大鼠海马神经细胞凋亡     

颞叶癫痫患者海马硬化神经元脱失的亚群特点

目的探讨颞叶癫痫患者海马硬化神经元脱失的亚群特点。方法颞叶癫痫患者中8例海马硬化和7例非海马硬化，以正常海马解剖为对照，观察两患者组海马各亚群神经元脱失情况。结果海马硬化组和非海马硬化组均有CA1、CA3锥体细胞和颗粒细胞脱失，海马硬化组明显。门区神经元脱失仅在海马硬化组可见。结论颞叶癫痫患者海马结构主要细胞脱失，门区神经元脱失是海马硬化的主要特点。海马硬化的形成与齿状回尤其是门区神经元的关系更为密切。     

锂-匹鲁卡品诱导癫痫持续状态大鼠海马神经元线粒体及细胞核的变化

BACKGROUND： Mitochondrial damage plays a key role in neuronal damage. OBJECTIVE： To observe ultrastructural damage to mitochondria and nuclei, as well as caspase-3 expression, in hippocampal CA3 neurons of lithium-pilocarpine-induced status epilepticus rats. DESIGN, TIME AND SETTING： The neuropathological, randomized, controlled study was performed at the Animal Experimental Center, Shandong University, China in May 2008. MATERIALS： A total of 75 healthy, adult, male, Wistar rats were randomly assigned into model （n = 45） and control （n = 30） groups. Lithium-pilocarpine （Sigma, USA） was used in this study. METHODS： Rats in the model group were intraperitoneally injected with lithium chloride （3 mEq/kg）, and 24 hours later with pilocarpine （45 mg/kg）, to induce seizures for 2 hours. Rats in the control group were intraperitoneally infused with the same volume of saline. Rat hippocampal CA3 tissue was obtained at 3, 12, and 24 hours following status epilepticus. MAIN OUTCOME MEASURES： Neuronal changes were observed under an optical microscope. Ultrastructural changes in mitochondria and nuclei were observed using an electron microscope. caspase-3 mRNA levels were quantified by semiquantitative RT-PCR. RESULTS： After 3 hours of status epilepticus, mitochondria with swollen cristae and ruptured membranes were observed by electron microscopy. Nuclei with marginated chromatin were observed after 24 hours status epilepticus. RT-PCR results demonstrated increased caspase-3 expression at 12 hours, and significantly increased expression at 24 hours following termination of status epilepticus. This was in accordance with acidophilia occurrence, as indicated by hematoxylin-eosin staining, and time of ultrastructural damage to nuclei. CONCLUSION： In lithium-pilocarpine-induced status epilepticus rat models, ultrastructural damage to mitochondria in hippocampal neurons occurred during early stages, followed by increased caspase-3 expression and nuclear changes. These results suggested that mitochondrial damage plays a key role in neuronal damage following status epilepticus.     

癫痫大鼠海马神经元和星形胶质细胞的病理演变

目的　探讨癫痫大鼠海马神经元和星形胶质细胞在点燃后各期的病理特点、时序及机制。方法　针对匹罗卡品癫痫大鼠模型,行Nissl、免疫组化和HE染色,观察海马神经元及星形胶质细胞的病理变化。结果　癫痫持续状态后超急性期（4h）,CA3区神经元呈嗜酸性变性、胞浆深染;急性期（24h）,嗜酸性变性最为显著,神经元固缩、核仁消失、突起断裂,星形胶质细胞水肿;缄默期（7d）,CA3、CA1区及门区神经元大量坏死、脱失,胶质增生肥大,海马构筑紊乱;慢性期（6w）,CA3、CA1区出现胶质瘢痕,遗有形态正常的神经元,且颗粒细胞层增厚。结论　癫痫时海马神经元先于星形胶质细胞发生病理改变,二者均参与癫痫发生。     

PTZ致痫大鼠海马区神经元损伤的研究

目的:为了解癫痫(Epilepsg,EP)发生后大脑海马区的损害情况,本文采用戊四氮诱导建立大鼠癫痫模型, 采用酶标免疫吸附法(EIA)和免疫组化染色法检测NSE的改变,使用电子显微镜研究超微结构的改变,探讨EP后脑组织的损坏情况。方法:雄性SD大鼠54只,随机分为对照组(A=13)及实验组(41只)。实验组腹腔注射(IP)PTZ 50mg/ kg体重1次,对照组IP生理盐水。根据EP发作分级,0-1级7只,视为B组,立即取脑:2级以上发作34只,随机抽样于EP发作后0h(C=10);6h(D=14);24h(E=10)断头。取脑前抽取躯干血,分离海马。A、D组随机抽取3只进行电镜观察。采用EIA法测试血清和海马NSE-值;以S-P免疫组化染色法染色,观察各组大鼠海马的NSE表达。结果:实验组海马和血清的NSE均明显高于对照组:即使无EP大发作,但有兴奋症状的大鼠,NSE亦高于对照组,表明也有脑组织损害。免疫组化染色显示:对照组海马组织几乎未见NSE的表达,即大发作后海马的NSE表达明显增加,但随时间推移而降低。电镜观察发现EP后大鼠海马CA1区的神经元细胞出现水肿、基质密度变淡、微丝溶解消失、细胞器减少、毛细血管周围间隙扩大等明显改变。结论:EP发作对大鼠海马区神经细胞造成了明显的损害。     

腺苷A1受体对杏仁核点燃癫痫大鼠海马神经元损伤作用机制

目的 探讨腺苷A1受体活性对点燃癫痫大鼠海马神经元损伤的作用.方法 选择84只SPF级雄性Wistar大鼠,根据随机数字表法将动物分为正常组、致痫组、致痫+腺苷A1 R拮抗剂(8-环戊-1,3-二丙基黄嘌呤,DPCPX)组、致痫+腺苷A1 R激动剂(2-氯化腺苷,2-CADO)组,每组21只.致痫组、致痫+DPCPX组、致痫+2-CADO组采用电刺激点燃癫痫模型.正常组未进行手术和电刺激致痫等处理;致痫组癫痫模型建立成功前后未注射任何药物;致痫+DPCPX组大鼠癫痫模型建立成功前1 h和成功后1 h尾部静脉注射0.3 mg/kg DPCPX;致痫+2-CADO组大鼠癫痫模型成功前1 h和成功后1 h尾部静脉注射0.6 mg/kg 2-CADO.采用苏木精-伊红染色法和TUNEL神经元凋亡测定法观察各组在癫痫模型建立成功后1 d、15 d、30 d时的海马CA3区组织学病理变化及神经元凋亡指数(AI)变化情况.结果 致痫组、致痫+DPCPX组、致痫+2-CADO组动物在点燃癫痫后1 d、15 d、30 d均出现不同程度的神经元细胞排列松散无规则,轮廓模糊,边缘欠清晰,胞核萎缩,胞浆空泡等神经元结构损害;相同时间点,致痫+DPCPX组的神经元结构损害程度较致痫组加重,致痫+2-CADO组较致痫组减轻.正常组在不同时间点的AI变化不明显(P>0.05),致痫组、致痫+DPCPX组、致痫+2-CADO组的AI随着癫痫发作时间的延长,AI逐渐增加(P<0.05);在相同时间点,致痫组、致痫+DPCPX组、致痫+2-CADO组的AI均明显高于正常组(P<0.05),致痫+DPCPX组的AI均明显高于致痫组(P<0.05);致痫+2-CADO组的AI明显低于致痫组和致痫+DPCPX组(P<0.05).结论 癫痫发作会引起神经元损伤和凋亡,其可能与腺苷A1 R活性降低,兴奋性氨基酸谷氨酸浓度增加有关,谷氨酸兴奋性增加可诱导神经元凋亡,这可能是癫痫发作后神经元损伤的机制之一.     

糖尿病大鼠海马组织中周期素依赖性激酶5表达的实验研究

目的：分析糖尿病大鼠海马组织中周期素依赖激酶5（CDK5）蛋白表达情况，探讨糖尿病影响学习与记忆的机制。方法：Y-迷宫评估大鼠学习与记忆成绩，用免疫组化法和Western blot检测海马区CDK5蛋白表达。结果：DM组大鼠第4周迷宫作业错误反应次数和全天总反应时间分别为（3．43±2．20）次、（115．42±36．64）s，对照组为（2．17±1．34）次，（90．83±20．27）s；CDK5蛋白表达相对水平为15．62±7．07，对照组为20．61±5．63，两组间差异有统计学意义（P〈0．05）。结论：糖尿病大鼠CDK5蛋白表达水平下降，学习记忆能力下降，提示CDK5可能参与了学习记忆过程。     

幼鼠早期癫痫持续状态对海马结构损伤的远期影响

目的　探讨幼鼠早期癫痫持续状态 (status epilepticus,SE)对成鼠后海马结构损伤的远期影响。方法　健康生后 1 5～ 2 0 d Wistar幼鼠 48只 ,随机分为生理盐水对照组和氯化锂 -匹罗卡品腹腔注射诱导的 SE组 ,并持续追踪至成鼠阶段 ,应用常规病理及电镜观察海马结构的形态学改变 ,同时应用 Timm组织化学染色方法进行苔藓纤维发芽研究。结果　约 2 /3 SE幼鼠发育至成鼠阶段后 ,海马结构的神经元仍可发现变性和坏死性改变 ,以 CA1区、CA3区和齿状回为重。 Timm染色见 CA3区有苔藓纤维发芽现象。约 1 /3 SE幼鼠发育至成鼠后未见海马结构损伤性改变。结论　幼鼠早期 SE造成的海马结构损伤性改变可持续至成鼠阶段 ,但存在个体差异 ,可能与个体耐受性有关。     

一种改良的胚胎大鼠颞叶海马区神经元的培养方法

目的:探索胚胎大鼠颞叶海马区神经元的改良培养方法。方法:在无血清培养基础上,采用改良的分离纯化法获取单细胞悬液,接种后在不同阶段通过加入不同配方的培养基进行培养,并进行免疫组化鉴定。结果:用该方法培养的颞叶海马区神经元细胞存活率高,生长状态良好,且βⅢ-tublin免疫染色为阳性,神经元细胞纯度可达90%以上。结论:改良分离、结合分阶段的不同培养条件是一种简单、高效的颞叶海马区神经元的纯化培养方法。     

Status Epilepticus Causes Selective Regional Damage and Loss of GABAergic Neurons in the Rat Amygdaloid Complex

In human epilepsy, the amygdala is often a primary focus for seizures. To analyse the status epilepticus-induced alterations in the amygdaloid circuitries which may later underlie epileptogenesis, we studied the amygdaloid damage in kainic acid and perforant pathway stimulation models of status epilepticus in the rat. We also studied the damage to inhibitory GABAergic neurons. In both models, the medial division of the lateral nucleus, the parvicellular division of the basal nucleus and portions of the anterior cortical and medial nuclei were damaged. In the kainate model, where the seizure activity was more severe, the accessory basal nucleus, amygdalohippocampal area, posterior cortical nucleus and periamygdaloid cortex were also damaged. Two weeks after kainate-induced seizures, 56% of the GABA-immunoreactive neurons remained in the lateral nucleus ( P < 0.05) and 25% in the basal nucleus ( P < 0.01). Further analysis showed that one subpopulation of damaged GABAergic neurons was immunoreactive for somatostatin (48% remaining in the lateral nucleus, P < 0.01; 33% in the basal nucleus, P < 0.01). In the perforant pathway stimulation model, the damage to somatostatin neurons was milder. According to our data, the initial insult, such as status epilepticus, selectively damages amygdaloid nuclei. The loss of inhibition may underlie the spontaneous generation of seizures and epileptogenesis. On the other hand, many amygdaloid output nuclei (magnocellular and intermediate division of the basal nucleus, the central nucleus) remained relatively undamaged, providing pathways for seizure spread and generation of seizure-related behavioural manifestations such as motor convulsions and fear response.     

冷却对大鼠难治性癫癎模型海马神经细胞存活率的影响

目的:探讨不同冷却温度和冷却时间对大鼠难治性癫癎模型海马神经细胞存活率的影响。方法:①6μmol.L-1荷包牡丹碱(Bic)+4-氨基吡啶(4-AP)联合刺激培养的大鼠海马组织切片(OHS)诱发癎样放电,制作难治性癫癎OHS模型;②在36℃和25℃培养1~24 h;③在36℃、30℃、25℃、20℃和15℃培养6 h;④分别测定OHS神经细胞的碘化丙啶(PI)摄取量。结果:Bic+4-AP联合刺激3 h后,摄取PI的神经细胞首先出现在海马的CA2区。随着刺激时间的延长,摄取PI神经细胞的分布范围扩散到其他区域,以CA3区最为明显。25℃冷却处理可以显著抑制神经细胞的PI摄取,然而,20℃、15℃深低温冷却处理可进使神经细胞的PI摄取。结论:①培养的大鼠海马组织CA2区的神经细胞对Bic+4-AP联合刺激最敏感,神经细胞的损伤与兴奋性刺激时间和海马的区域有关;②冷却处理神经细胞的保护作用与冷却的温度和时间有关。     

Hippocampal Pyramidal Cell Loss in Human Status Epilepticus

A pilot case-control quantitative study of the hippocampus in patients with severe status epilepticus was performed to identify specific patterns of pyramidal cell loss. Pyramidal cell densities from five patients who died following status epilepticus were compared with five normal controls and five controls matched for age, hypoxia/ischemia, previous epilepsy, and alcohol abuse. Neuronal densities were greatest in the normal control group and least in patients with status epilepticus. Significant reductions were identified in Sommer's sector (prosubiculum and CA1) as well as in CA3 when compared to normal controls.     

Convulsive Status Epilepticus in Children

Summary: Status epilepticus (SE) occurs most commonly in infancy and childhood. Children with prior neurological abnormalities are most susceptible. More than 90% of cases are convulsive and the majority are generalized. SE may occur in the setting of an acute illness, in patients with established epilepsy or as a first unprovoked seizure. The etiology can be classified as idiopathic, remote symptomatic, febrile, acute symptomatic, or associated with a progressive encephalopathy. The morbidity and mortality of status have dramatically declined in recent years. Overall mortality in recent pediatric series was 3–10%, with almost all fatalities associated with acute central nervous system insults or progressive neurologic disorders. Neurological sequelae in children with idiopathic or febrile status are rare. Neurologically normal children with SE as their first unprovoked seizure have the same risk of experiencing subsequent seizures of any type as children who present with a brief first seizure. The risk of recurrent episodes of convulsive SE approaches 50% in neurologically abnormal children but is very low in neurologically normal children. The favorable outcome of SE in children may be related to advances in therapy and to the resistance of the immature brain to damage from seizures.     

Nonconvulsive Status Epilepticus in Adults and Children

Summary: Nonconvulsive status epilepticus (SE) accounts for approximately one-quarter of all cases of SE. The actual proportion may be higher because patients with nonconvulsive SE may go unidentified. This disorder may be divided into generalized (absence) or partial (complex partial) forms. Nonconvulsive SE may occur de novo or in patients with epilepsy. Absence SE is considered more frequent and is characterized by a continuous neurocognitive alteration. Complex partial SE may be associated with recurrent seizure activity and a cycling of the clinical states. Treatment includes antiepileptic drug(s) (AEDs) and avoidance of seizure precipitants. Electrophysiological studies are necessary to confirm the diagnosis of nonconvulsive SE and to monitor the response to AED therapy. Prompt recognition and treatment may be necessary to avoid neurological morbidity in select patients. Epilepsy with continuous spikes and waves during slow sleep (ESES) and the Landau-Kleffner syndrome are two rare childhood disorders that are difficult to classify but may be appropriate to include in a discussion of nonconvulsive SE.