TRPC6在匹罗卡品致痫大鼠海马苔藓纤维出芽中的作用

目的 观察传统型瞬时受体电位通道6(TRPC6)蛋白在匹罗卡品致痫大鼠海马中的表达变化,探讨其在海马苔藓纤维出芽中的作用.方法 72只SD大鼠随机分为实验组(n=60)和对照组(n=12).实验组采用氯化锂-匹罗卡品腹腔注射法建立颞叶癫痫模型;对照组腹腔注射等量无菌生理盐水.实验组按癫痫持续状态(SE)后1d、7d、15d、30 d和60 d分为5个亚组,每亚组12只大鼠.以上各亚组及对照组再分为2个小组,分别进行Western blot检测TRPC6及突触重建标志蛋白Synaptophysin在海马中的表达和Timm染色观察海马苔藓纤维出芽并评分.结果 实验组TRPC6蛋白表达量在SE后1d达高峰(P＜0.01),其他时间点均显著高于对照组(P＜0.01).Synaptophysin蛋白表达量在SE后7d、15d、30 d和60 d显著增加(7 d:P＜0.05;15 d、30 d、60 d:P＜0.01),30 d达峰值(P＜0.01).实验组大鼠齿状回内分子层在SE后7d出现Timm颗粒,并呈进行性增加.结论 TRPC6可能参与了苔藓纤维出芽这一过程.     

颞叶癫痫大鼠海马TrkB mRNA及其蛋白表达的动态变化

目的 探讨颞叶癫痫发作大鼠海马TrkB mRNA及其蛋白表达的动态变化特征。方法 建立匹罗卡品(PILO)颞叶癫痢大鼠模型,应用原位杂交及免疫组织化学方法分别检测致(?)大鼠海马齿状回、CA3区及CA1区TrkB nRNA及其蛋白质表达的变化。结果 PILO致(?)后3～6 h,海马齿状回颗粒细胞层、CA1、CA3区锥体细胞层TrkB mRNA表达显著增高(P<0.01),稍后TrkB蛋白表达也随之增高。第7-30 d,TrkB mRNA及其蛋白在齿状回、CA3区呈现第二次表达增强。结论在癫(?)发作早期,TrkB表达增强,提示其可能参与急性癫痫状态的发生;后期表达增强则可能参与了海马的可塑性反应而与慢性自发性发作形成有关。     

颞叶癫癎大鼠海马TrkB mRNA及其蛋白表达的动态变化

目的探讨颞叶癫瘸发作大鼠海马TrkB mRNA及其蛋白表达的动态变化特征.方法建立匹罗卡品(PILO)颞叶癫癎大鼠模型,应用原位杂交及免疫组织化学方法分别检测致瘸大鼠海马齿状回、CA3区及CAi区TrkB mRNA及其蛋白质表达的变化.结果 PILO致瘸后3～6 h,海马齿状回颗粒细胞层、CA1、CA3区锥体细胞层TrkBmRNA表达显著增高(P＜0.01),稍后TrkB蛋白表达也随之增高.第7～30d,TrkBmRNA及其蛋白在齿状回、CA3区呈现第二次表达增强.结论在癫癎发作早期,TrkB表达增强,提示其可能参与急性癜癎状态的发生;后期表达增强则可能参与了海马的可塑性反应而与慢性自发性发作形成有关.     

单剂量匹罗卡品诱导小鼠癫痫及其海马神经损伤的研究

目的 探索不同剂量匹罗卡品单次腹腔注射对诱发小鼠癫痫及对海马损伤的影响,为癫痫建模提供参考。方法将100只健康的C57BL/6小鼠随机分为正常对照组、3个不同剂量匹罗卡品(250 mg/kg、290 mg/kg、350 mg/kg)腹腔注射组。比较3组的建模成功率、死亡率,通过免疫组化染色观察神经元和胶质细胞的数量变化,分析海马区组织的病变情况。结果 匹罗卡品250 mg/kg组小鼠的Racine评分4级以上发作率为12%,无死亡; 290 mg/kg组小鼠的4级以上发作率为70%,死亡率为32%; 350 mg/kg组小鼠的4级以上发作率为86%,死亡率为56%。免疫组化染色结果显示:与正常对照组相比,3个不同剂量匹罗卡品组小鼠诱发癫痫后,神经元数量均显著减少,小胶质细胞和星形胶质细胞数量均显著增加;但250 mg/kg组小鼠的活化小胶质细胞数量无显著变化,而其他两组显著增多。结论 匹罗卡品290 mg/kg单次注射诱发小鼠癫痫模型的成功率较高、死亡率较低,且海马区损伤明显,可以作为癫痫小鼠建模的参考方法。     

氯化锂-匹罗卡品致痫幼鼠海马结构损伤的形态学及苔藓纤维发芽研究

目的 观察幼鼠致痫后海马的组织病理学改变。方法 采用氯化锂－匹罗卡品腹腔注射制成幼鼠癫痫持续状态模型，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的研究。结果 海马区神经元可见变性、坏死改变，以CA1区、CA3区为重。Timm染色见齿状回内分子层和CA3区下锥体层苔藓纤维发芽增加。结论 （1）氯化锂－匹罗卡品诱导的幼鼠癫痫持续状态可造成海马区神经元损伤；（2）幼鼠癫痫持续状态后海马CA1、CA3区神经元损伤较重；（3）幼鼠癫痫持续状态后可致苔藓纤维发增加。     

匹罗卡品癫痫模型中突触素Ⅰ的表达及苔藓纤维出芽的动态变化

目的探讨癫痫发生过程中突触素Ⅰ(SYNⅠ)在海马和齿状回的表达及齿状回苔藓纤维出芽的动态变化。方法建立匹罗卡品癫痫持续状态模型,用图像分析系统测定海马和齿状回不同时点SYNⅠ免疫反应吸光度值．Neo-timms’染色观察齿状回苔藓出芽的演变。结果SYNⅠ在海马和齿状回的表达于癫痫状态后2d、7d出现降低,14d开始升高,30d、60d表达明显增高；齿状回内分子层于14d开始出现苔藓纤维出芽,大鼠在同期开始出现自发发作。结论在癫痫状态后2d即出现了突触可塑性的变化,14d后由于神经轴突的再生,齿状回内分子层出现苔藓纤维出芽,形成了兴奋性的环路,可能是癫痫反复自发发作的病理基础,SYNⅠ及苔藓纤维出芽较好的反应了神经可塑性的变化。     

锂-匹罗卡品致痫大鼠海马胶质纤维酸性蛋白的表达及意义

目的观察其海马经HE染色后组织病理学、胶质纤维酸性蛋白免疫反应阳性表达细胞在LPS中各观察时间点海马CA1、CA3、齿状回的表达,探讨其致机制。方法锂-匹罗卡品急性诱导SD癫痫持续状态模型鼠形成后,采用免疫组化和图像分析方法观察海马HE染色组织病理学、胶质纤维酸性蛋白免疫反应阳性表达细胞。结果模型组各时间点海马细胞形态出现病理性改变,部分细胞脱失,胞浆浓缩,胞核固缩深染;胶质纤维酸性蛋白免疫反应阳性表达细胞亦显著上调（P〈0.05）。结论Pilo诱导SD大鼠癫痫发作后存在显著的海马神经元结构和胶质细胞的损伤,以胶质细胞损伤更显著,胶质纤维酸性蛋白持续高表达可能是这种功能异常的胶质细胞增生的重要原因,也可能是锂-匹罗卡品致癫痫发作的重要因素之一。     

边缘癫痫实验模型海马内突触体素表达

目的探讨癫痫时突触体素(P^38)在海马表达的时间变化及意义。方法建立匹罗卡品边缘癫痫模型，用图像分析系统测定海马不同时间点P^38免疫反应吸光度值。结果P^38免疫反应性在海马呈现两次高峰：致痫后3～6h在海马门区及CA3区P^38短期升高，30～60dCA3区呈现第2次高峰。在内分子层，从第7天开始直至第60天P^38呈进行性增多，且与Neo—Timm染色结果相平行。结论P^38在海马第2次表达增高，平行于苔藓纤维出芽，与自发性发作形成有关。急性期表达增高则与癫痫持续状态的产生与维持有关。     

匹罗卡品诱发成年大鼠普遍癫痫与难治性癫痫海马神经发生的变化

背景：神经发生包括细胞增殖、迁移、分化和存活等,是人和多数哺乳动物部分脑区产生新生神经元的过程,主要分布在侧脑室下区和海马齿状回。癫痫可导致海马齿状回的神经发生改变,BrdU是目前公认最理想检测未成熟细胞增殖的标记物之一。 目的：观察匹罗卡品诱发成年大鼠癫痫后神经发生的特点,以及普通癫痫与难治性癫痫神经发生的差异。 设计、时间及地点：随机分组,细胞分子生物学实验,于2006-08/2007-06在华中科技大学同济医学院中心实验室及附属协和医院中心实验室完成。 材料：选用健康Sprague-Dawley雄性大鼠100只,随机分为2组,对照组8只,实验组92只,分为普通癫痫组,自发发作组,难治性癫痫组和非耐药组。匹罗卡品为武汉晶美公司产品,兔抗鼠BrdU抗体为美国sigma公司产品,辣根过氧化物酶标记的羊抗兔IgG为武汉博士德公司产品。 方法：对照组大鼠腹腔注射生理盐水;实验组腹腔注射匹罗卡品15mg/kg,最多注射4次,出现癫痫持续状态的大鼠注射水合氯醛终止发作。致癫大鼠癫痫发作终止后6h腹腔注射BrdU,观察自发发作情况。以脑电图、自发发作频率持续时间,无自发发作为普通癫痫组,有自发发作为自发发作组。行卡马西平灌胃2周并记录发作频率,对卡马西平治疗无效,发作频率减少<50%的为难治性癫痫组,治疗有效即发作频率减少>50%为非耐药组。普通癫痫组分别于注射后第1,2,3,7,14,21和28d取鼠脑海马部做冠状连续切片。非耐药组和难治性癫痫组的大鼠,再次行腹腔注射BrdU,每次为50mg/kg,连续注射4次,每次间隔2h,48h后取脑海马部制作石蜡切片。 主要观察指标：脑海马部切片行免疫组化染色,镜下观察不同时间点BrdU阳性细胞的分布、形态和数量及注射匹罗卡品后大鼠癫痫发作状况。 结果：匹罗卡品第1次注射后所有大鼠无癫痫发作,第2次注射发作16只,第3次注射发作42只,第4次注射后发作11只,14只大鼠4次注射仍无癫痫发作,9只大鼠癫痫持续状态后死亡,77只进入结果分析。神经发生主要位于海马颗粒细胞层和齿状回。与对照组比较,普通癫痫组BrdU阳性细胞明显增多（P<0.01）,难治性癫痫组新生细胞较普通癫痫组明显减少（P<0.01）,神经发生减少。癫痫后第2天BrdU 阳性细胞数目开始增加,14-15d达到高峰,1个月后回到初始水平。 结论：与普通癫痫相比,难治性癫痫可导致神经发生减少。     

匹罗卡品致疒间大鼠海马GAP-43与TrkB基因表达及其意义

目的探讨生长相关蛋白(GAP-43)和脑源性神经营养因子(BDNF)受体TrkB基因在匹罗卡品致疒间大鼠海马的表达及其意义.方法应用原位杂交组织化学方法研究匹罗卡品(PILO)致疒间大鼠海马GAP-43及TrkB mRNA表达的变化.结果匹罗卡品致癫疒间持续状态后3～6小时,海马齿状回颗粒细胞、CA3区及CA1区锥体细胞层TrkB mRNA表达显著高于对照组(P<0.01或0.05);在慢性期第7～30天,呈现第2次表达增强.致疒间后6～12小时,正常状态下并不表达GAP-43的大鼠海马颗粒细胞其GAP-43 mRNA表达较对照组显著增高(P<0.01),24小时～7天表达减少,在癫疒间慢性期表达再次高于对照组.结论 GAP-43及TrkB是颞叶癫疒间病理基础--海马苔藓纤维出芽的重要分子机制;BDNF对苔藓纤维的作用部分是通过GAP-43实现的.     

损伤性癫痫模型大鼠海马和额叶突触蛋白的动态表达

目的 通过观察FeCl2皮层注射致损伤性癫痫(PTE)模型大鼠海马、额叶突触蛋白P38的表达变化.探讨突触可塑性在PTE发病机制中的作用. 方法 健康成年雄性SD大鼠采用随机数字表法分为正常对照组(n=5)、假手术组(n=12)、模型组(n=20).采取立体定向皮层注射FeCl2(0.1 moL/L,10μL)建立PTE模型,假手术组注入等量生理盐水,正常对照组不做处理.观察各组大鼠EEG的变化并应用免疫组织化学方法 检测大鼠造模后不同时间点(1 h、7 d、14 d、30 d)海马、额叶P38的表达. 结果大多数模型组大鼠在注射FeCl2后不久记录到癫痫样放电;与假手术组比较,模型组不同时间点右侧额叶P38表达减少.差异有统计学意义(P<0.05);与正常对照组和假手术组比较,致痫1h后,CA3区多形层、辐射层、腔隙层和齿状回(DG)分子层P38表达均无明显变化,7 d后P38表达增加,维持到30d,差异均有统计学意义(P<0.05). 结论 与突触蛋白P38表达相关的突触可塑性变化在PTE的发病机制中可能起重要作用.     

Expression of vitamin D receptor mRNA in the hippocampal formation of rats submitted to a model of temporal lobe epilepsy induced by pilocarpine

Vitamin D (VD), is a steroid hormone with multiple functions in the central nervous system (CNS), producing numerous physiological effects mediated by its receptor (VDR). Clinical and experimental studies have shown a link between VD dysfunction and epilepsy. Along these lines, the purpose of our work was to analyze the relative expression of VDR mRNA in the hippocampal formation of rats during the three periods of pilocarpine-induced epilepsy. Male Wistar rats were divided into five groups: (1) control group; rats that received saline 0.9%, i.p. and were killed 7 days after its administration (CTRL, n = 8), (2) SE group; rats that received pilocarpine and were killed 4 h after SE (SE, n = 8), (3) Silent group—7 days; rats that received pilocarpine and were killed 7 days after SE (SIL 7d, n = 8), (4) Silent group—14 days; rats that received pilocarpine and were killed 14 days after SE (SIL 14d, n = 8), (5) Chronic group; rats that received pilocarpine and were killed 60 days after the first spontaneous seizure, (chronic, n = 8). The relative expression of VDR mRNA was determined by real-time PCR. Our results showed an increase of the relative expression of VDR mRNA in the SIL 7 days, SIL 14 days and Chronic groups, respectively (0.060 ± 0.024; 0.052 ± 0.035; 0.085 ± 0.055) when compared with the CTRL and SE groups (0.019 ± 0.017; 0.019 ± 0.025). These data suggest the VDR as a possible candidate participating in the epileptogenesis process of the pilocarpine model of epilepsy.     

2004/大鼠杏仁核点燃癫痫不同脑区BDNF及其受体TrkB的变化

目的 检测大鼠杏仁核点燃癫痫后不同脑区脑源性神经营养因子（BDNF）及其受体TrkB的表达与定位。方法 建立大鼠杏仁核点燃癫痫模型,应用免疫组化方法观察点燃鼠不同脑区不同点燃时程BDNF及TrkB的表达及含量。结果 点燃后大鼠颞叶及海马BDNF随着点燃次数的增加而升高,并持续至点燃后 49d;TrkB的表达也是随着点燃次数的增加而升高,并持续至点燃后7d（改变同BDNF）,点燃1周后表达逐渐减少,至点燃后7周时基本恢复正常。结论 BDNF及TrkB直接参与癫痫的发生与发展。早期具有保护作用,但随着表达的进一步增加,又促进癫痫的发生发展,并一定程度上促进了癫痫发作后的神经细胞凋亡及脑损伤过程。     

Brain‐derived neurotrophic factor but not vesicular zinc promotes TrkB activation within mossy fibers of mouse hippocampus in vivo

The neurotrophin receptor, TrkB receptor tyrosine kinase, is critical to central nervous system (CNS) function in health and disease. Elucidating the ligands mediating TrkB activation in vivo will provide insights into its diverse roles in the CNS. The canonical ligand for TrkB is brain‐derived neurotrophic factor (BDNF). A diversity of stimuli also can activate TrkB in the absence of BDNF, a mechanism termed transactivation. Zinc, a divalent cation packaged in synaptic vesicles along with glutamate in axons of mammalian cortical neurons, can transactivate TrkB in neurons and heterologous cells in vitro. Yet the contributions of BDNF and zinc to TrkB activation in vivo are unknown. To address these questions, we conducted immunohistochemical (IHC) studies of the hippocampal mossy fiber axons and boutons using an antibody selective for pY816 of TrkB, a surrogate measure of TrkB activation. We found that conditional deletion of BDNF resulted in a reduction of pY816 in axons and synaptic boutons of hippocampal mossy fibers, thereby implicating BDNF in activation of TrkB in vivo. Unexpectedly, pY816 immunoreactivity was increased in axons but not synaptic boutons of mossy fibers in ZnT3 knockout mice that lack vesicular zinc. Marked increases of BDNF content were evident within the hippocampus of ZnT3 knockout mice and genetic elimination of BDNF reduced pY816 immunoreactivity in these mice, implicating BDNF in enhanced TrkB activation mediated by vesicular zinc depletion. These findings support the conclusion that BDNF but not vesicular zinc activates TrkB in hippocampal mossy fiber axons under physiological conditions. J. Comp. Neurol. 522:3885–3899, 2014. © 2014 Wiley Periodicals, Inc.     

Increased densities of AMPA GluR1 subunit proteins and presynaptic mossy fiber sprouting in the fascia dentata of human hippocampal epilepsy

In human hippocampal epilepsy, there is a consistent pathology of cell loss and reactive synaptic reorganization of ‘excitatory' mossy fibers (MF) into the inner molecular layer (IML) of the fascia dentata (FD). In this study, neo-Timm's histochemistry of MFs and immunocytochemistry of GluR1 were used to determine, in patients with or without hippocampal sclerosis (HS), if there was a correlation between aberrant supragranular (IML) mossy fiber sprouting and increased densities of AMPA GluR1 subunit proteins in the IML of the FD. Computerized quantified densitometric grey values of Timm and GluR1 densities were corrected for the densities of granule cell losses using cell counts. In the IML of the HS group, despite the losses of granule cells, mossy fiber sprouting was significantly greater (P<0.000001) and GluR1 protein densities were significantly higher (P<0.0005) than those of the non-HS group. Unlike supragranular mossy fiber sprouting, which was limited to the IML, the increased GluR1 stainings were distributed throughout the whole molecular layer. For all cases, MF synaptic reorganization in the supragranular ML was correlated with GluR1 subunit protein densities in the IML (R=0.784, P<0.0093). These data demonstrate that in the human epileptic fascia dentata, there are significantly increased AMPA GluR1 subunit proteins associated with aberrant MF synaptic reorganizations. This suggests that the hyperexcitability of sclerotic hippocampus occurs, at least in part, from the associated changes of both presynaptic mossy fiber glutamatergic neoinnervation and increased GluR1 subunit proteins in the dendritic domains of the FD.     

The cellular and synaptic location of activated TrkB in mouse hippocampus during limbic epileptogenesis

Understanding the mechanisms of limbic epileptogenesis in cellular and molecular terms may provide novel therapeutic targets for its prevention. The neurotrophin receptor tropomyosin‐related kinase B (TrkB) is thought to be critical for limbic epileptogenesis. Enhanced activation of TrkB, revealed by immunodetection of enhanced phosphorylated TrkB (pTrkB), a surrogate measure of its activation, has been identified within the hippocampus in multiple animal models. Knowledge of the cellular locale of activated TrkB is necessary to elucidate its functional consequences. Using an antibody selective to pTrkB in conjunction with confocal microscopy and cellular markers, we determined the cellular and subcellular locale of enhanced pTrkB induced by status epilepticus (SE) evoked by infusion of kainic acid into the amygdala of adult mice. SE induced enhanced pTrkB immunoreactivity in two distinct populations of principal neurons within the hippocampus—the dentate granule cells and CA1 pyramidal cells. Enhanced immunoreactivity within granule cells was found within mossy fiber axons and giant synaptic boutons. By contrast, enhanced immunoreactivity was found within apical dendritic shafts and spines of CA1 pyramidal cells. A common feature of this enhanced pTrkB at these cellular locales is its localization to excitatory synapses between excitatory neurons, presynaptically in the granule cells and postsynaptically in CA1 pyramidal cells. Long‐term potentiation (LTP) is one cellular consequence of TrkB activation at these excitatory synapses that may promote epileptogenesis. J. Comp. Neurol. 521:499–521, 2013. © 2012 Wiley Periodicals, Inc.     

铁离子诱发癫痫鼠脑海马胶质增生和突触重建的研究

目的 探讨海马突触重建及胶质增生与创伤性癫痫发病机制的关系。方法 应用铁离子杏仁体注射制作创伤性癫痫模型，免疫组化染色观察胶质纤维酸性蛋白(GFAP)和突触生长蛋白(p38)表达水平。结果 注入铁离子后，注射侧海马锥体细胞大量脱失，双侧海马组织各区均有胶质细胞增生，齿状回突触重建，这些变化持续到30d。结论 杏仁体注射铁离子后可继发引起海马组织的神经元脱失、反应性胶质细胞增生和异常的神经元放电环路，可能是形成慢性特发性癫痫的病理学基础。     

Manganese-enhanced magnetic resonance imaging detects mossy fiber sprouting in the pilocarpine model of epilepsy

Purpose: Mossy fiber sprouting (MFS) is a frequent finding following status epilepticus (SE). The present study aimed to test the feasibility of using manganese‐enhanced magnetic resonance imaging (MEMRI) to detect MFS in the chronic phase of the well‐established pilocarpine (Pilo) rat model of temporal lobe epilepsy (TLE). Methods: To modulate MFS, cycloheximide (CHX), a protein synthesis inhibitor, was coadministered with Pilo in a subgroup of animals. In vivo MEMRI was performed 3 months after induction of SE and compared to the neo‐Timm histologic labeling of zinc mossy fiber terminals in the dentate gyrus (DG). Key Findings: Chronically epileptic rats displaying MFS as detected by neo‐Timm histology had a hyperintense MEMRI signal in the DG, whereas chronically epileptic animals that did not display MFS had minimal MEMRI signal enhancement compared to nonepileptic control animals. A strong correlation (r = 0.81, p < 0.001) was found between MEMRI signal enhancement and MFS. Significance: This study shows that MEMRI is an attractive noninvasive method for detection of mossy fiber sprouting in vivo and can be used as an evaluation tool in testing therapeutic approaches to manage chronic epilepsy.     

Mossy fibre reorganization in the hippocampus of prion protein null mice

Mice lacking prion protein (PrP-null) are resistant to transmissible spongiform encephalopathies. However, the normal functions of this highly conserved protein remain controversial. This study examines whether PrP-null mice develop normal neuronal pathways, specifically the mossy fibre pathway, within the hippocampus. Timm stained hippocampal sections from the PrP-null group had more granules than the controls in: the granule cell layer, the inner molecular layer of the dentate gyrus, and the infrapyramidal region of CA3. This resembles the mossy fibre collateral and terminal sprouting seen in certain epilepsies. The abnormal connectivity might be predicted to promote epileptiform activity, but extracellular electrophysiological recordings from the granule cell layer revealed a reduced excitability in the PrP-null group, both with and without blockade of GABA_A receptor-mediated inhibition. We propose that reorganization of neuronal circuity is a feature of PrP-null mice.