海藻氨酸致癫癎状态大鼠海马区神经元损伤与Mg2+作用的研究

目的观察海藻氨酸(KA)诱导的癫癎状态(SE)大鼠海马神经元的形态学改变和Mg2+的神经保护作用.方法选用成年雄性Wistar大鼠75只,随机分为KA组、Mg2+组和生理盐水对照组.用KA诱导大鼠SE 3 h,Mg2+组大鼠在注射KA前腹腔内注射硫酸镁100 mg/kg,在癫癎发作终止后72 h将动物处死,分别用光镜和电镜观察海马神经元形态学改变.结果 KA组大鼠注射KA后(16.1±4.7)min出现癫癎发作,Mg2+组大鼠为(25.4±6.2)min,两组比较差异有显著性(P<0.05).KA组和Mg2+组大鼠在海马区均出现了嗜酸性神经元,Mg2+组大鼠神经元损伤程度明显低于KA组.结论 KA诱导的SE可导致海马神经元坏死,而 Mg2+作为兴奋性氨基酸拮抗剂对海马神经元具有保护作用.     

红藻氨酸致癫痫持续状态大鼠海马neuropilin-2 mRNA及其蛋白表达的研究

目的研究轴索导向分子NPN-2mRNA及其蛋白对癫痫持续状态(SE)后大鼠海马内神经纤维外向性生长和突触重建中的调控作用。方法采用侧脑室内注射红藻氨酸(KA)制作TLE大鼠模型,用Nissl染色、原位杂交和免疫组织化学的方法,分别检测致SE后1d、1w、2w、3w、4w大鼠海马齿状回(DG)、CA1区、CA3区、门区神经元丢失程度以及NPN-2mRNA及其蛋白的表达。结果 KA致SE后1d开始出现神经元丢失,至4w神经元丢失明显增多。KA致SE后1d,NPN-2mRNA及其蛋白在DG和CA1区表达明显下降,持续至3w(P0.01),4w恢复至正常(P0.05);NPN-2mRNA及其蛋白在门区、CA3区表达实验组与对照组无明显差别(P0.05)。结论 KA致SE后,海马DG及CA1区神经元下调NPN-2mRNA及其蛋白的表达,促进DG及CA1区神经纤维外向性生长和突触的重建。     

癫痫持续状态后大鼠海马区钾离子通道Kv1.3的表达研究

目的研究氯化锂-匹罗卡品致癫痫持续状态(status epilepticus,SE)后大鼠海马区钾离子通道Kv1.3的表达及分布变化,探讨钾离子通道Kv1.3与癫痫发作的相关性。方法 48只健康雄性sprague-dawley大鼠随机平分为实验组和对照组,每组继续随机分为6 h、1 d、2 d和3 d 4个观察时间点亚组(n=6)。通过大鼠脑电监测记录大鼠脑电变化情况,通过尼氏染色观察脑组织病理改变,采用免疫组织化学染色和Western-blot方法检测各时间点大鼠海马区Kv1.3的表达及分布变化。结果 (1)脑电监测:正常大鼠脑电图表现为波幅较均匀一致的α波,痫性发作后开始出现慢波、棘波,波幅、节律不规则,SE过程中表现为长程的棘波活动。(2)尼氏染色:SE后6 h未发现明显形态学及神经元数量改变;SE后1 d,海马区神经元结构松散,神经元数量减少;SE后2 d、3 d,海马区神经元进一步减少,且出现神经元肿胀、变形、尼氏小体减少甚至消失。(3)免疫组织化学染色和Western-blot检测:SE后2 d,Kv1.3在海马CA_3和CA_1区表达较对照组明显减少(P0.05)。SE后6 h、1 d、3 d,Kv1.3在海马CA_3和CA_1区表达较对照组无明显变化(P0.05)。SE后6 h、1 d、2 d、3 d,Kv1.3在海马DG区表达较对照组无明显差异(P0.05)。结论 Kv1.3的表达下调可能与癫痫发作相关。     

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     

癫痫持续状态大鼠内质网应激预适应对海马神经元保护作用的实验研究

目的 探讨2-脱氧葡萄糖诱导内质网应激预适应对癫痫持续状态大鼠海马神经元的保护作用及其可能机制。方法 采用2-脱氧葡萄糖连续腹腔注射诱导内质网应激,并在此基础上制备氯化锂-匹罗卡品癫痫持续状态大鼠模型。Nissl染色观察癫痫持续状态后海马神经元损伤情况、计数海马CA1和CA3区存活神经元数目;免疫组织化学检测海马CA3区内质网应激标志物葡萄糖调节蛋白78（GRP78）和X盒结合蛋白1（XBP-1）表达变化。结果 与癫痫持续状态组相比,癫痫持续状态后第7天时内质网应激预适应组大鼠海马存活神经元数目增加,以CA1区显著（t=5.353,P=0.000）。癫痫持续状态组大鼠发作后6 h,海马CA3区GRP78和XBP-1表达水平升高且高于对照组（均P=0.000）,于发作第2天达峰值水平（均P=0.000）;内质网应激预适应组大鼠发作前海马CA3区GRP78和XBP-1表达即高于对照组（均P=0.000）,GRP78在发作后24 h和2 d时维持在峰值水平（均P=0.000）,XBP-1在发作后24 h达峰值水平（P=0.000）;内质网应激预适应组大鼠海马CA3区GRP78和XBP-1表达在癫痫持续状态前,以及癫痫持续状态后6、12、24 h均高于癫痫持续状态组（均P=0.000）,至第2和7天时与癫痫持续状态组之间差异无统计学意义（P〉0.05）。结论 经2-脱氧葡萄糖诱导的内质网应激预适应对癫痫持续状态大鼠海马神经元具有保护作用,而XBP-1-GRP78信号转导通路的活化可能是其机制之一。     

马桑内酯致大鼠癫痫持续状态后海马神经细胞凋亡的观察

观察马桑内酯（ｃｏｒｉａｒｉａｌａｃｔｏｎｅ，ＣＬ）诱导鼠癫痫持续状态（ＳＥ）时海马细胞中ＤＮＡ损伤及凋亡现象。方法用流式细胞术检测海马细胞中ＤＮＡ状态，用免疫组织化学方法显示海马谷氨酸阳性细胞，并以流式细胞术免疫荧光法测定海马细胞中ＢＣＬ－２样蛋白含量。结果ＳＥ后海马细胞中有ＤＮＡ损伤断裂；海马ＣＡ３区谷氨酸阳性细胞数量减少，着色变淡；海马细胞中ＢＣＬ－２样蛋白增加。结论ＳＥ可诱导海马细胞ＤＮＡ损伤进而凋亡；ＳＥ时谷氨酸过量释放可造成突触后靶细胞损伤。ＢＣＬ－２样蛋白增加可能是ＢＣＬ－２家族蛋白共同变化的结果，是细胞自身的保护机制，以抗损伤和凋亡。     

经鼻给予TGFβ1对癫痫持续状态大鼠海马神经元的保护作用

目的探讨经鼻腔给予TGFβ1(transforming growth factor beta1,TGFβ1)对氯化锂-匹罗卡品所致癫痫持续状态(status epilepticus,SE)大鼠海马神经元的保护作用及其潜在的机制。方法健康雄性SD大鼠60只,随机分为转化生长因子(TGF)组、匹罗卡品(Pilo)组和正常对照组(control)。建立氯化锂-匹罗卡品癫痫持续状态模型。应用TUNEL染色、Fluoro-Jade B(FJB)荧光染色法分别观察各组大鼠海马神经元的原位凋亡及变性死亡情况。采用免疫组化方法检测凋亡相关基因caspase-3的蛋白表达。结果 SE后24h、48h、72h,TGF组大鼠海马FJB、TUNEL、caspase-3阳性细胞均较Pilo组显著减少(P<0.05);72h最为明显(P<0.01)。结论经鼻(IN)给予TGFβ1可以显著抑制或减轻癫痫持续状态大鼠海马神经元的变性与凋亡,从而发挥神经保护作用。其潜在的神经保护机制可能涉及下调caspase-3蛋白表达。     

癫痫持续状态后神经元损伤机制研究进展

凋亡和坏死是癫痫持续状态后神经元损伤的两种形式。凋亡有内源性和外源性两种途径,其核心环节是线粒体膜通透性的改变和细胞色素C的释放,最终通过caspase-3的激活导致核内染色体DNA的阶段性降解。最新研究表明,神经元坏死的过程中也存在程序性细胞死亡机制的激活,其间涉及细胞色素C的释放和caspase-3的激活。兴奋毒性损伤的强度和线粒体的功能状态决定了癫痫持续状态后神经元的死亡形式。     

癫痫持续状态后海马神经元凋亡的形态学证据及意义

癫痫持续状态（ｓｔａｔｕｓｅｐｉｅｐｔｉｃｕｓ，ＳＥ）可造成选择性神经元损害。近来研究发现这些脑组织中神经元死亡可能是通过凋亡（ａｐｏｐｔｏｓｉｓ）机制。腹腔注射贝美格（Ｂｅｍｅｇｒｉｄｅ）诱导ＳＥ，研究了鼠ＳＥ后脑损害中的神经元凋亡现象，以ＨＥ染色、电镜、荧光（ＡｃｒｉｄｉｎｅＯｒａｎｇｅ，ＡＯ）细胞核染色方法观察细胞形态，以流式细胞术及凝胶电冰鉴定ＤＮＡ片断。ＳＥ后２４小时，海马中的易损神经元死亡具有凋亡特征：①光镜及电镜观察到细胞核内染色体凝聚和边及；②阳性ＡＯ着色细胞核；③流式细胞术及凝胶电冰显示具有ＤＮＡ片断。而且有Ⅰ型和Ⅱ型两种形式的凋亡。因此ＳＥ引起海马损害中神经元有通过调亡机制发生死亡．     

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。     

Excitatory amino acid transporter 2 downregulation correlates with thalamic neuronal death following kainic acid‐induced status epilepticus in rat

Recurrent seizures without interictal resumption (status epilepticus) have been reported to induce neuronal death in the midline thalamic region that has functional roles in memory and decision‐making; however, the pathogenesis underlying status epilepticus‐induced thalamic neuronal death is yet to be determined. We performed histological and immunohistochemical studies as well as cerebral blood flow measurement using 4.7 tesla magnetic resonance imaging spectrometer on midline thalamic region in Sprague–Dawley rats (n = 75, male, 7 weeks after birth, body weight 250–300 g) treated with intraperitoneal injection of kainic acid (10 mg/kg) to induce status epilepticus (n = 55) or normal saline solution (n = 20). Histological study using paraffin‐embedded specimens revealed neuronal death showing ischemic‐like changes and Fluoro‐Jade C positivity with calcium deposition in the midline thalamic region of epileptic rats. The distribution of neuronal death was associated with focal loss of immunoreactivity for excitatory amino acid transporter 2 (EAAT2), stronger immunoreaction for glutamate and increase in number of Iba‐1‐positive microglial cells showing swollen cytoplasm and long processes. Double immunofluorescence study demonstrated co‐expression of interleukin‐1 beta (IL‐1β) and inducible nitric oxide synthase (iNOS) within microglial cells, and loss of EAAT2 immunoreactivity in reactive astrocytes. These microglial alterations and astrocytic EAAT2 downregulation were also observed in tissue without obvious neuronal death in kainic acid‐treated rats. These results suggest the possible role of glutamate excitotoxicity in neuronal death in the midline thalamic region following kainic acid‐induced status epilepticus due to astrocytic EAAT2 downregulation following microglial activation showing upregulation of IL‐1β and iNOS.     

海人酸致痫大鼠海马CA3区神经元线粒体超微结构损伤及caspase-3的表达变化

目的观察海人酸(KA)诱导的癫痫持续状态(SE)大鼠海马CA3区神经元线粒体超微结构的损伤及caspase-3的表达变化.方法用KA诱导大鼠SE 2h.于SE终止后第3、12、24小时取海马,电镜观察线粒体的超微结构,免疫组化方法检测caspase-3的表达.腹腔内注射生理盐水的大鼠设为对照组.结果SE终止后3 h,电镜下可见线粒体肿胀及膜完整性的破裂.caspase-3的表达于SE后1 2 h较对照组增加,平均阳性细胞数及灰度值分别为10.49±0.68及45.57±2.27(P＜0.05);于SE后24 h,分别为37 36±0.57及11 5.24±1 22(P＜0.01).结论在实验性SE模型中,海马神经元线粒体超微结构的损伤早于caspase-3的表达,提示线粒体的损伤可能是SE后神经元损伤的关键环节.     

巢蛋白阳性星形胶质细胞与癫痫持续状态后海马区胶质瘢痕形成的相关性研究

目的 了解癩痫持续状态(SE)后7d海马各区巢蛋白(nestin)阳性星形胶质细胞表达及数目的变化,探讨其与SE导致海马区胶质瘢痕形成的关系.方法 SD大鼠随机分为SE组和对照组,应用匹罗卡品建立SE大鼠模型;在SE后7d处死大鼠行盲法免疫荧光组化实验,观察大鼠海马各区nestin与胶质纤维酸性蛋白单克隆抗体(GFAP...     

Cortical laminar necrosis related to prolonged focal status epilepticus

Cortical laminar necrosis (CLN) is radiologically defined as high intensity cortical lesions on T1 weighted MRI images following a gyral distribution. Histopathologically, CLN is characterised by pannecrosis of the cortex involving neurones, glial cells, and blood vessels. It has been reported to be associated with hypoxia, metabolic disturbances, drugs, and infections. We present two patients who developed CLN and permanent neurological deficits after prolonged and repeated focal status epilepticus. The possible mechanisms leading to CLN in these patients are discussed, together with the implications of prompt and aggressive treatment in similar cases.     

Effects of status epilepticus on extracellular amino acids in the hippocampus

Extracellular amino acids were followed in the hippocampus during sustained seizures induced by systemic administration of kainic acid (KA) or bicuculline (BC). KA epilepsy was associated with marked increases in phosphoethanolamine (PEA) and taurine. Alanine and ethanolamine were moderately raised while other amino acids were unaffected. BC seizures encompassed a slightly different pattern of alterations. In contrast to KA seizures, BC epilepsy had no effect on taurine. Significant increments were observed for PEA and alanine while elevations of ethanolamine were subtle. In both types of seizures, glutamate and GABA remained unaffected extracellularly, probably due to efficient recapture mechanisms.     

托吡酯对癫痫大鼠海马神经元超微结构及bcl-2表达的影响

目的观察托吡酯对癫痫大鼠海马神经元超微结构及bcl-2表达的影响,以探讨托吡酯可能的神经保护机制。方法将大鼠随机分为正常对照组、海人酸组(KA)和托吡酯预处理组(TPM)。采用海人酸腹膜腔注射制作癫痫持续状态(SE)模型。在SE模型制作前,TPM组大鼠用TPM(18mg/(kg·d))灌胃15d,同时用等量生理盐水给KA组大鼠灌胃。正常对照组大鼠不作任何处理。在痫性发作终止后6、24、48h取海马,电镜观察神经元的超微结构,免疫组化方法检测bcl-2的表达。结果KA组神经元呈凋亡特征。TPM组神经元结构大致正常,但出现核仁边聚和细胞器增多现象,亦观察到少量凋亡神经元。KA组于SE后6h观察到bcl-2表达增高(与对照组相比,P<0.05),于24h开始减弱,48h仅有微弱表达。TPM组在24h点有bcl-2的强表达(P<0.001),并持续至48h。结论托吡酯预处理能减轻癫痫大鼠神经元的损伤,其神经保护作用可能与bcl-2蛋白的表达上调有关。     

Lack of neuronal damage in atypical absence status epilepticus

PURPOSE: Whether status epilepticus of nonconvulsive epileptic seizures is harmful still remains controversial. To investigate this, the presence and/or extent of neuronal damage in patients with absence status epilepticus (ASE) and patients with complex partial status epilepticus (CPSE) was examined and compared. METHODS: Neuron-specific enolase (NSE) in CSF was examined in the patients with ASE and compared with that of the patients having CPSE. Clinical aspects of these patients also were investigated. RESULTS: CSF NSE levels in ASE patients were lower than those of CPSE patients and were considered as the normal values. No clinical symptoms indicated neuronal damage in the ASE patients. CONCLUSIONS: This study suggests that ASE does not induce neuronal damage. Serum NSE is not always correlated to CSF NSE, and determination of serum NSE levels may be an inappropriate method of estimating neuronal damage in some cases of ASE.     

Neuropathology of limbic status epilepticus induced by electrical stimulation of naive rats

Abstract

Neuronal damage in relation to the duration of seizure was studied in limbic status epilepticus (SE) induced by electric stimulation of naive rats. Adult Sprague-Dawley rats were stimulated at the right amygdala to induce SE. To stop the seizures, diazepam was given to different groups of rats at 0.5 h (n = 4), 7 h fn = 6), 2 h (n = 6), and 3-4 h (r\ = 8) of SE. Eighteen hours after the end of SE, the rats were perfusion fixed. Naive (n = 6) and sham-operated (n = 4) rats served as controls. Horizontal paraffin sections were stained with acid fuchsin and cresyl violet. Neuronal damage was absent after 30 min of SE. Status epilepticus of I h or longer duration regularly caused neuronal damage to the cerebral cortex, thalamus, hippocampus, amygdala, and pars reticulata of the substantia nigra. Damage in the cerebral cortex predominated in the entorhinal, temporal, and pyriform regions. In the hippocampus, the dentate hilus was most severely affected, followed by CA3 and CAT. Damage to the dentate granule layer was mild. Further studies of the pathophysiology of excitotoxicity may help to protect patients from sequels of status epilepticus such as neuronal damage and epilepsy. [Neurol Res 1999; 21: 399-403]