颞叶癫痫大鼠海马CA1区Sema3C、Np1的表达变化研究

目的探讨颞叶癫痫的发病机制。方法取健康雄性SD大鼠制成颞叶癫痫模型，用免疫组织化学和原位杂交技术对匹罗卡品致痫后不同时间点CA1区的Sema3C mRNA、Np1 mRNA和蛋白表达进行分析。结果在匹罗卡品致痫后7d，实验组CA1区Sema3C、Np1的表达明显低于对照组（P〈0．01）。结论CA1区Sema3C、Np1的表达下凋可能参与了海马CA1区内的轴突出芽机制。     

颞叶癫(癎)大鼠海马轴突导向分子Sema3F及其受体Np2表达的变化

目的研究颞叶癫大鼠海马轴突导向分子Sema3F及其受体Np2表达的变化。方法给SD大鼠腹腔注射匹罗卡品、氯化锂制作颞叶癫模型。用免疫组化法和原位杂交技术对致后不同时间点大鼠海马CA1区、CA3区、齿状回的Sema3F mRNA、Np2 mRNA和蛋白表达进行检测,并与正常对照组比较。结果颞叶癫大鼠致后7d、15d,海马CA1区、CA3区Sema3F mRNA、Np2 mRNA和蛋白的表达明显低于正常对照组(P<0.05~0.01),致后30d、60d表达与正常对照组差异无统计学意义;而齿状回Sema3F mRNA、Np2 mRNA和蛋白的表达与正常对照组的差异无统计学意义。结论颞叶癫大鼠海马CA1区、CA3区Se-ma3F、Np2表达在致后早期明显下调,而在慢性期恢复正常。     

颞叶癫大鼠海马轴突导向分子Sema3F及其受体Np2表达的变化

目的 研究颞叶癫(癎)大鼠海马轴突导向分子Sema3F及其受体Np2表达的变化.方法 给SD大鼠腹腔注射匹罗卡品、氯化锂制作颞叶癫(癎)模型.用免疫组化法和原位杂交技术对致(癎)后不同时间点大鼠海马CA1区、CA3区、齿状回的Sema3F mRNA、Np2 mRNA和蛋白表达进行检测,并与正常对照组比较.结果 颞叶癫(癎)大鼠致(癎)后7 d、15 d,海马CA1区、CA3区Sema3F mRNA、Np2 mRNA和蛋白的表达明显低于正常对照组(P＜0.05～0.01), 致(癎)后30 d、60 d表达与正常对照组差异无统计学意义;而齿状回Sema3F mRNA、Np2 mRNA和蛋白的表达与正常对照组的差异无统计学意义.结论 颞叶癫(癎)大鼠海马CA1区、CA3区Sema3F、Np2表达在致(癎)后早期明显下调,而在慢性期恢复正常.     

红藻氨酸诱导癫痫发作大鼠海马EphA5受体及其配体ephrinA3基因表达变化的研究

目的研究在红藻氨酸(Kainic acid,KA)诱导的损伤型颞叶癫痫(Mesial temporal lobe epilepsy,MTLE)的大鼠海马中,轴突导向因子EphA5受体及其配体ephrinA3基因表达的变化,探讨EphA5/ephrinA3与癫痫后海马兴奋性神经网络形成的作用和关系。方法侧脑室内微量注射KA,建立KA诱导的成年大鼠MTLE模型,用原位杂交法检测癫痫发作1d、1周、2周、3周、4周大鼠海马内EphA5/ephrinA3 mRNA的表达,定量分析表达的动态变化。结果EphA5/ephrinA3 mRNA于癫痫发作后1周,在海马齿状回颗粒细胞层和CA_3区锥体细胞层开始增强,2周达到高峰,4周恢复接近对照组水平。结论在KA所致的癫痫持续状态(Status epilepsy,SE)中,海马神经元通过增强EphA5/ephrinA3 mRNA的表达。调控MTLE大鼠海马内苔藓纤维和突触的重建,是癫痫后海马新的稳定的异常兴奋性神经网络形成的可能机制。     

红藻氨酸致颞叶癫痫大鼠海马内Semaphorin3C、Semaphorin3F基因表达的研究

目的研究神经轴索导向分子Sem aphorin3C(Sem a3C),Sem aphorin3F(Sem a3F)mRNA对颞叶癫痫(TLE)大鼠海马神经轴索环路重建的调控作用。方法采用侧脑室内注射红藻氨酸(KA)制作TLE大鼠模型,用N issl染色及原位杂交的方法,分别检测致痫后1d、1w、2w、3w、4w大鼠海马的齿状回(DG),CA1区、CA3区神经细胞丢失程度以及Sem a3C、Sem a3F mRNA的表达。结果KA致痫后1d始出现神经元丢失,至4w神经元丢失明显增多。KA致痫后1w,Sem a3C、Sem a3F mRNA在海马的CA1区、Sem a3F mRNA在海马的CA3区表达明显下降,持续至3w(P<0.01),4w时恢复至正常(P>0.05);Sem a3C、Sem a3F mRNA在DG的表达,Sem a3C在CA3区的表达,实验组与对照组均无明显差别(P>0.05)。结论KA致痫后海马CA1区神经元下调Sem a3C、Sem a3F mRNA的表达,CA3区神经元下调Sem a3F mRNA的表达,可能促进TLE大鼠海马神经轴索环路重建。     

颞叶癫痈大鼠海马内Rnd1 mRNA及蛋白表达变化

目的：动态观察小分子GTPase Rho家族的Rnd1 mRNA及其蛋白在氯化锂-毛果芸香碱（匹罗卡品）致痫大鼠模型海马中的表达变化，探讨其在颞叶癫痫发生发展中的作用。方法：在氯化锂-毛果芸香碱颞叶癫痫模型中应用逆转录聚合酶链反应（RT—PCR）检测癫痫持续发作（SE）后各时间点海马内Rnd1 mRNA的表达变化，并运用免疫组织化学染色法及Neo—Timm染色法分别检测齿状回门区、CA1区及CA3区中该蛋白在不同时间点的表达变化及苔藓纤维出芽（MFS）情况。结果：实验发现模型组于SE后8h内即出现Rnd1表达上调，SE后约1d达高峰，7d左右回复至对照组水平，此后其mRNA表达水平与对照组相似；而免疫组化染色发现Rnd1蛋白表达从SE后8h内即开始上调，约3d达高峰，至7d虽略有回落，但仍高于对照组水平，且这种情况可一直持续至慢性期。结论：急性期海马齿状回门区Rnd1表达上调可能通过促进MFS的发生参与了颞叶癫痫的发生。     

癫痫持续发作时间与大鼠海马苔藓纤维发芽程度及自发性痫性发作的关系

目的探讨癫痫持续状态(SE)发作时间与致痫大鼠海马苔藓纤维发芽(MFS)程度及自发性痫性发作的关系。方法 104只雄性成年SD大鼠,随机分为对照组和3个SE实验组,建立氯化锂-重复低剂量匹罗卡品致痫大鼠模型;诱发SE30min(A组)、60min(B组)、90min(C组)后注射水合氯醛终止发作。各组大鼠自SE终止发作后于相同实验条件下普通饲养45d,观察大鼠行为及脑电图(EEG)的变化,记录自发性痫性发作的发生率。通过苏木精-伊红染色、Nissl染色和Timm硫化银组织化学染色方法观察各实验组海马MFS情况。结果氯化锂-重复低剂量匹罗卡品成功诱导大鼠SE的发生,发作程度均达Ⅳ级以上,EEG类似人类颞叶癫痫。80%的大鼠癫痫持续状态均发展为自发痫性发作,与SE时间无关。与对照组相比,实验A、B、C三组双侧海马CA3区均表现MFS(P0.05)。实验B组与A、C组相比,CA3区MFS明显增加(P0.05)。结论氯化锂-重复低剂量匹罗卡品可诱导SE,癫痫持续发作60min后终止的大鼠海马CA3区MFS明显增加,SE发作时间与海马MFS程度并不一定呈正相关。     

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。     

颞叶癫痫神经元型钙粘素mRNA表达研究

目的研究匹罗卡品诱导的颞叶癫痫神经元型钙粘素的表达变化.方法用氯化锂加匹罗卡品诱导SD大鼠颞叶癫痫模型,特异性探针原位杂交检测神经元型钙粘素mRNA表达.结果对照组动物神经元型钙粘素mRNA在皮层和海马各区均有表达,给药后4 h和12 h神经元型钙粘素mRNA在CA1、CA3和齿状回均表达下降,24 h开始恢复,注药后3 d神经元型钙粘素mRNA表达显著高于对照组,7 d表达最高.结论神经元型钙粘素mRNA在颞叶癫痫表达呈双相变化.     

氯化锂-匹罗卡品致痫大鼠海马结构中CLC-2、CLC-3氯通道表达变化的研究

目的 研究ClC-2、ClC-3氯通道在氯化锂-匹罗卡品大鼠慢性癫痫模型中分布和表达的变化,探讨其在癫痫发作病理机制中的作用.方法 Wistar大鼠采用随机数字表法分成致痫组(60只)与对照组(20只),其中致痫组根据处死及处理时间又分为24h组、14d组与30d组,每组20只.致痫组复制氯化锂-匹罗卡品大鼠慢性癫痫模型,在发作后24h、14d、30d时,分别予以:(1)免疫组化染色,观察ClC-2、ClC-3氯通道蛋白在海马表达的分布情况及其致病后不同时点的吸光度(A)值的变化;(2)RT-PCR,观察ClC-2、ClC-3氯通道mRNA在致痫后不同时点的变化.结果 (1)与对照组比较,致痫后14d至30d,致痫组免疫反应阳性神经元数和A值明显减少和降低,差异有统计学意义(P<0.05);ClC-2 mRNA表达降低,差异有统计学意义(P<0.05).(2)与对照组比较,致痫组致痫后24 h,海马CA1、CA3及齿状回各层ClC-3免疫反应阳性神经元数和A值明显增加和升高,差异有统计学意义(P<0.05);ClC-3氯通道mRNA表达明显增加,差异有统计学意义(P<0.05).结论 癫痫慢性期的发作和ClC-2氯通道的减少有关.     

电针百会和大椎穴对癫痫大鼠海马CA3和DG区ephrinA5表达的影响

目的探讨电针百会和大椎穴对颞叶癫痫大鼠海马组织中CA3和DG区ephrin A5的调控作用。方法将30只SpragueDawley(SD)大鼠随机分为对照组、癫痫组和电针+癫痫组,每组各10只。建立氯化锂―匹罗卡品颞叶癫痫大鼠模型。造模成功的大鼠电针百会和大椎穴治疗8周后,分别取3组大鼠海马组织,采用实时荧光定量PCR(q RT-PCR)检测各组大鼠海马CA3和DG区ephrin A5 m RNA水平表达变化;采用Western blotting和免疫组织化学(免疫组化)法检测各组大鼠海马CA3和DG区ephrin A5蛋白水平表达变化。结果 q RT-PCR结果显示:与对照组相比,癫痫组大鼠海马组织中ephrin A5 m RNA表达下调(P <0.05)。通过8周电针百会和大椎穴连续治疗后,ephrin A5 m RNA水平上调(P <0.05)。Western blotting结果显示:ephrin A5蛋白水平变化趋势与m RNA水平相一致。免疫组化结果显示:在CA3区,癫痫组ephrin A5蛋白水平下调;电针后ephrin A5蛋白水平上调。而在DG区与对照组相比,癫痫组和电针+癫痫组,ephrin A5蛋白水平变化不明显。结论电针百会和大椎穴的抗癫痫作用机制很可能与ephrin A5在海马CA3区中的调控机制密切相关。     

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。     

Seizure-related changes in the glutamate R2 and R5 receptor genes expression in the rat hippocampal formation

Summary The expression of mRNA coding for AMPA selective glutamate (Glu) R2 receptor and kainate selective GluR5 receptor was studied in the rat hippocampal formation in two animal models of limbic seizures evoked by systemic administration of pilocarpine (400 mg/kg ip) or kainate (15 mg/kg ip). As shown by an in situ hybridization study, pilocarpine decreased the GluR2 flip mRNA level in CA1 and CA3 areas of the hippocampus after 3h and kainate after 24 h, e.g. at the time preceding neuronal degeneration. No changes in the GluR2 flop or GluR5 mRNA level were found in those regions. In the dentate gyrus, resistant to neurodegeneration, pilocarpine and kainate differentialy affected the expression of GluR2 and GluR5 mRNAs. After 72 h pilocarpine, but not kainate, increased the GluR2 flop mRNA level and decreased the flip one, which suggests attenuation of the GluR2 sensitivity. On the other hand, kainate, elevated the GluR2 flip and GluR5 mRNA level in the dentate gyrus after 72 h. All in all the above data suggest that changes in the GluR2 gene expression may play some role in the neuronal damage to vulnerable areas (CA1, CA3). However, differences in the kainate- and pilocarpine-induced changes in the dentate gyrus at the late time points indicate that alterations in the stoichiometry of GluR2 forms or GluR5 gene expression in this brain region are not a common causal factor responsible for delayed neuronal hyperexcitability.     

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。     

Differential paired-pulse responses between the CA1 region and the dentate gyrus are related to altered CLC-2 immunoreactivity in the pilocarpine-induced rat epilepsy model

The epileptic hippocampus shows differential paired-pulse responses between the dentate gyrus and the CA1 region. However, little data are available to explain this phenomenon. In the present study, we identified the relationship between regional differences of paired-pulse response and voltage gated Cl(-) channel 2 (CLC-2)/vesicular GABA transport (VGAT) expression in a pilocarpine-induced rat model. During epileptogenic periods, paired-pulse inhibitions in the dentate gyrus and the CA1 region were markedly reduced. After recurrent seizure onset, paired-pulse inhibition in the dentate gyrus was markedly enhanced, while that in the CA1 region more reduced. Unlike VGAT, CLC-2 immunoreactivity was markedly reduced in the hippocampus during epileptogenic periods and was re-enhanced only in the dentate gyrus after recurrent seizure onset. Linear regression analysis showed an inverse proportional relationship between alterations in CLC-2 immunoreactivity and changes in normalized population spike amplitude ratio within the CA1 region and the dentate gyrus. Therefore, our findings suggest that the regionally specific alterations in CLC-2 immunoreactivity after SE may determine the properties of paired-pulse responses in the hippocampus of the pilocarpine-induced rat epilepsy model.     

Upregulation of axon guidance molecules in the adult central nervous system of Nogo‐A knockout mice restricts neuronal growth and regeneration

Adult central nervous system axons show restricted growth and regeneration properties after injury. One of the underlying mechanisms is the activation of the Nogo‐A/Nogo receptor (NgR1) signaling pathway. Nogo‐A knockout (KO) mice show enhanced regenerative growth in vivo, even though it is less pronounced than after acute antibody‐mediated neutralization of Nogo‐A. Residual inhibition may involve a compensatory component. By mRNA expression profiling and immunoblots we show increased expression of several members of the Ephrin/Eph and Semaphorin/Plexin families of axon guidance molecules, e.g. EphrinA3 and EphA4, in the intact spinal cord of adult Nogo‐A KO vs. wild‐type (WT) mice. EphrinA3 inhibits neurite outgrowth of EphA4‐positive neurons in vitro. In addition, EphrinA3 KO myelin extracts are less growth‐inhibitory than WT but more than Nogo‐A KO myelin extracts. EphA4 KO cortical neurons show decreased growth inhibition on Nogo‐A KO myelin as compared with WT neurons, supporting increased EphA4‐mediated growth inhibition in Nogo‐A KO mice. Consistently, in vivo, Nogo‐A/EphA4 double KO mice show increased axonal sprouting and regeneration after spinal cord injury as compared with EphA4 KO mice. Our results reveal the upregulation of developmental axon guidance cues following constitutive Nogo‐A deletion, e.g. the EphrinA3/EphA4 ligand/receptor pair, and support their role in restricting neurite outgrowth in the absence of Nogo‐A.     

Expression of metabotropic glutamate receptor 1alpha in the hippocampus of rat pilocarpine model of status epilepticus.

The expression of metabotropic glutamate receptor 1alpha was studied in the rat hippocampus after pilocarpine-induced status epilepticus by Western blot and immunocytochemistry at both light and electron microscopic levels. At 1 day after pilocarpine-induced status epilepticus, there was marked decrease in metabotropic glutamate receptor 1alpha immunoreactivity at the border between stratum oriens and alveus in CA1 and CA3, and in the hilus of dentate gyrus. Between 3 and 31 days after pilocarpine-induced status epilepticus, metabotropic glutamate receptor 1alpha-immunoreactive dendrites and cell bodies in the border between stratum oriens and alveus gradually reappeared. Upregulation of metabotropic glutamate receptor 1alpha, however, was observed in the stratum oriens of CA1 at day 1, but returned to baseline by day 7. By electron microscopy, the metabotropic glutamate receptor 1alpha-immunoreactive product was demonstrated only in the post-synaptic elements in the border between the stratum oriens and alveus of CA1 and the hilus of the dentate gyrus in both control and experimental rats. At 1 day after pilocarpine-induced status epilepticus, metabotropic glutamate receptor 1alpha-immunoreactive degenerating neurons were identified in the border between stratum oriens and alveus of CA1 and the hilus of the dentate gyrus. At 7 and 31 days, many degenerating axons were also found. Present results suggest that excitoneurotoxicity mediated through post-synaptic metabotropic glutamate receptor 1alpha may be involved in degeneration and death of interneurons in the hilus of dentate gyrus, and the border between stratum oriens and alveus of CA1 in the early stage after pilocarpine-induced status epilepticus.     

Expression of GAP-43 in the Granule Cells of Rat Hippocampus After Seizure-induced Sprouting of Mossy Fibres: In Situ Hybridization and Immunocytochemical Studies

The axonal growth-associated protein GAP-43 is believed to play some role in the synaptic remodelling that takes place in the hippocampus of adult rats after certain experimental lesions. GAP-43 mRNA is highly expressed in adult CA3 pyramidal cells but almost absent in the dentate granule cells. We analysed whether the sprouting of granule cell axons, the mossy fibres of the hippocampus, caused by kainic acid-induced seizures in adult rats was associated with any induction of GAP-43 mRNA in granule cells and with any changes in the immunostaining pattern of GAP-43 in the hippocampus. Increased GAP-43 mRNA expression was found to be induced in granule cells 18, 24 and 30 h after a systemic injection of kainic acid which induced generalized seizures in adult rats, and returned to control levels by 48 h post-treatment. No effect was observed in other regions of the hippocampus. However, when kainic acid was injected into 15-day-old rats, which responded with generalized seizures but no sprouting of mossy fibres, there was no induction of GAP-43 mRNA in the granule cells, suggesting a close relation between GAP-43 expression and sprouting of these cells. Seven days after kainic acid injections, GAP-43 immunostaining was decreased in the inner molecular layer of the dentate gyrus except for a thin supragranular band, whereas 30 days after treatment all animals showed increased GAP-43 immunoreactivity in the whole inner molecular layer. Since collaterals of mossy fibres grow in the inner molecular layer after kainic acid-induced seizures, these results support the theory that GAP-43 plays a role in synaptic remodelling in the adult central nervous system.     

EphrinA4 mimetic peptide targeted to EphA binding site impairs the formation of long-term fear memory in lateral amygdala

Fear conditioning leads to long-term fear memory formation and is a model for studying fear-related psychopathologies conditions such as phobias and posttraumatic stress disorder. Long-term fear memory formation is believed to involve alterations of synaptic efficacy mediated by changes in synaptic transmission and morphology in lateral amygdala (LA). EphrinA4 and its cognate Eph receptors are intimately involved in regulating neuronal morphogenesis, synaptic transmission and plasticity. To assess possible roles of ephrinA4 in fear memory formation we designed and used a specific inhibitory ephrinA4 mimetic peptide (pep-ephrinA4) targeted to EphA binding site. We show that this peptide, composed of the ephrinA4 binding domain, interacts with EphA4 and inhibits ephrinA4-induced phosphorylation of EphA4. Microinjection of the pep-ephrinA4 into rat LA 30 min before training impaired long- but not short-term fear conditioning memory. Microinjection of a control peptide derived from a nonbinding E helix site of ephrinA4, that does not interact with EphA, had no effect on fear memory formation. Microinjection of pep-ephrinA4 into areas adjacent to the amygdala had no effect on fear memory. Acute systemic administration of pep-ephrinA4 1 h after training also impaired long-term fear conditioning memory formation. These results demonstrate that ephrinA4 binding sites in LA are essential for long-term fear memory formation. Moreover, our research shows that ephrinA4 binding sites may serve as a target for pharmacological treatment of fear and anxiety disorders.