雌激素和姜黄素对海人酸杏仁核点燃大鼠行为学、脑电图及海马神经元损伤的影响

目的了解雌激素和姜黄素对海人酸(kainic acid,KA)杏仁核点燃大鼠癫痫发作的影响。方法给去势的雌性大鼠添加雌激素治疗,添加姜黄素治疗,或添加雌激素和姜黄素治疗,比较各组大鼠致痫后癫痫发作的行为学、脑电图和海马神经元损伤的变化。结果给雌激素治疗的大鼠重型发作(Racine 4/5级)评分最高,而雌激素加姜黄素治疗组评分最低(P<0.05)。脑电图的变化与行为学的改变基本一致。致痫后大鼠注射KA侧海马CA3区、CA4区可见到明显的细胞损伤,而该侧海马CA1区、齿状回区(DG)及对侧海马CA3区、CA1区及DG区神经元损害不明显。雌激素组大鼠双侧海马CA3区均出现加重的神经元损害,姜黄素组及雌激素加姜黄素组大鼠海马注射对侧CA3区存活神经元较雌激素组明显增加(P<0.01)。结论高水平的雌激素可以加重癫痫的发作,给姜黄素治疗可以减轻大鼠海马CA3区神经元损害。     

红藻氨酸致痫大鼠海马神经元凋亡及其与caspase-3关系的研究

目的　研究大鼠癫痫发作后海马神经元凋亡及其与天冬氨酸特异性半胱氨酸蛋白酶 -3 (cysteinylasparate-specific proteinase,caspase-3 )表达的关系。方法　采用红藻氨酸 (kainic acid,KA)诱导大鼠癫痫模型 ,以原位末端标记 (TUNEL)及透射电镜检测癫痫发作后 6h及 1、3、7d海马神经元凋亡 ;半定量 RT-PCR及免疫组化法检测 caspase-3 m RNA及 caspase-3阳性表达。结果　KA致痫后 1 d,海马 CA1、CA3及 CA4区开始出现凋亡细胞 ,3 d时明显增多 ,7d时最多。 3个时间组相应区域间凋亡神经元数比较差异均有显著性 (P<0 .0 0 1 )。透射电镜观察可见典型的凋亡细胞形态学改变。 RT-PCR结果显示 ,KA致痫后 6h,海马组织 caspase-3 m RNA表达较对照组显著增高 (P <0 .0 5 ) ,1、3、7d caspase-3 m RNA仍持续高水平表达 (P <0 .0 5 )。免疫组化结果显示 ,KA致痫后 1 d,海马 CA1、CA3、CA4区开始出现 caspase-3阳性表达 ,3 d时阳性表达进一步增强 ,7d时表达最强。结论　凋亡参与 KA致痫大鼠癫痫发作后海马神经元迟发性死亡过程 ,caspase-3可能在癫痫后神经元凋亡过程中具重要的作用。     

戊四氮点燃大鼠海马CA3区钙超载与亚低温对点燃大鼠脑保护作用的研究

目的 海马CA1区钙超载是否在癫痫的发病机制中起主要作用及亚低温对癫痫是否有治疗意义。方法用荧光倒置显微镜来测定癫痫状态下海马CA1、CA3区钙超载的情况，并用钙离子拮抗剂尼莫地平作用于海马脑片看钙超载的变化。然后将大鼠分为头皮温度为41℃、37℃、32℃、26℃的4组，通过对4组点燃大鼠行为学和海马组织病理学的观察来看亚低温对癫痫的脑保护作用。结果癫痫大鼠海马CA1，CA3区钙超载高于对照组．CA1区钙超载高于CA1区。在尼莫地平的作用下CA1区钙超载明显降低。组织病理学改变显示CA1区是海马区神经元变性、坏死最明显的部位。而亚低温下癫痫的发作程度和神经元变性、坏死最轻。结论钙超载参与了癫痫的发病机制，其中海马CA3区的钙超载在癫痫发病机制中起主要作用。而亚低温对脑有保护作用。     

二苯乙烯苷对大鼠癫痫引发的学习记忆功能的影响及保护作用

目的：研究二苯乙烯苷（tetrahydroxy stilbene glucoside, TSG）对癫痫大鼠脑损伤的保护作用及可能机制。方法：将SD大鼠随机分为假手术组、模型组、TSG干预组,应用立体定向脑室内微量注射的方法建立海人藻酸（KA）诱导的大鼠癫痫模型。5d后通过Morris水迷宫实验测定大鼠学习记忆功能;取脑行Nissl染色观察大鼠海马神经元的形态及数目改变。结果：与假手术组相比,模型组大鼠学习记忆能力明显降低,海马CA1区神经元大量丢失,结构紊乱。而TSG干预组可使癫痫引发的学习记忆能力降低的情况得到改善,抑制海马CAl区神经元的丢失,改善神经元结构。结论：TSG对癫痫引发的脑损伤,尤其是对海马区神经元迟发性凋亡具有明显的改善作用。     

低剂量伽玛刀照射对癫痫大鼠皮层及海马NMDA受体亚基表达的影响

目的观察低剂量伽玛刀照射对癫痫大鼠皮层和海马N-甲基-D-天氡氨酸(N-methyl-Daspartate,NMDA)受体亚基表达的影响。方法根据动物是否致痫及接受伽玛刀照射,将大鼠分为4组:对照组、伽玛刀组、药物致痫组、伽玛刀+药物组。腹腔连续注射戊四氮(pentylenetetrazole,PTZ)制备癫痫大鼠模型,以双侧额叶为照射靶区对大鼠进行低剂量伽玛刀照射,边缘剂量为15Gy。观察并记录各组大鼠伽玛刀照射前、后癫痫发作情况,并于伽玛刀照射后12周后留取脑组织,分别利用免疫组化及免疫蛋白印迹法对大鼠皮层及海马NMDA受体亚基NR1、NR2A和NR2B进行检测。结果对照组及伽玛刀组大鼠无痫性发作表现,与药物致痫组大鼠相比,伽玛刀+药物组大鼠经低剂量伽玛刀照射后12周,痫性发作明显减轻(P0.05)。与对照组相比,药物致痫组大鼠额叶皮层及海马CA1、CA3区NR1、NR2A和NR2B表达均明显增强(P0.05),阳性神经元数目及平均吸光度值均明显增加(P0.05);与药物致痫组比较,伽玛刀+药物组额叶皮层及海马CA1、CA3区NR1、NR2A和NR2B表达均明显降低(P0.05),阳性神经元数目及平均吸光度值明显减少(P0.05);伽玛刀组与对照组无明显差别(P0.05)。结论癫痫大鼠额叶皮层及海马NR1、NR2A及NR2B亚单位蛋白表达增强,低剂量伽玛刀照射可能引起癫痫大鼠皮层及海马NMDA受体亚基表达减少,这可能是低剂量伽玛刀抑制癫痫发作的分子机制之一。     

海人酸致痫大鼠海马神经元凋亡研究

目的　研究大鼠癫痫发作后海马神经元凋亡的时空分布。方法　采用海人酸 (KA)诱导大鼠癫痫模型 ,以原位末端标记 (TUNEL)及透射电镜检测癫痫发作后 6h、1d、3d、7d海马神经元凋亡。结果　对照组及KA致痫后 6h组 ,海马区均未发现凋亡细胞。KA致痫后 1d ,海马CA1、CA3及CA4区开始出现凋亡细胞 ,3d时明显增多 ,7d时最多。KA致痫后 1d、3d、7d ,海马CA1锥体层线性长度1mm的TUNEL阳性细胞数分别为 (6 .6 0± 3.6 9)个、(13.5 7± 5 .17)个和 (2 5 .96± 4 .87)个 ;CA3区分别为 (6 .4 8± 2 .4 5 )个、(13.89± 2 .5 2 )个和 (2 8.80± 5 .39)个 ;CA4区分别为 (4 .6 0± 1.4 5 )个、(12 .2 0± 2 .0 4 )个和 (2 5 .2 0± 5 .83)个。 3个时间组相应区域凋亡神经元数比较均存在显著性差异(P <0 .0 0 1)。透射电镜观察可见典型的凋亡细胞形态学改变。结论　凋亡参与KA致痫大鼠癫痫发作后海马神经元迟发性死亡过程。     

亚低温对戊四氮诱导癫痫发作的影响

目的观察戊四氮诱导癫痫发作的形式变化及不同温度下癫痫大鼠海马组织病理学的变化和计数CA3区残存的神经元数量.方法雄性SD大鼠分为上述不同温度的四组,用冰袋降温、白炽灯泡升温的方法来控制温度.将控制好温度的大鼠用戊四氮诱导癫痫发作,在相同的时间内观察大鼠发作形式的变化.HE染色后观察海马区组织病理学的改变,并选择组织学损害最明显的区域在高倍镜(40×10)下计数神经元的丢失.结果高温状态下癫痫发作程度最重,神经元丢失最严重,低温下癫痫发作程度较轻,神经元丢失也较少,亚低温下癫痫发作程度最轻,持续时间也最短,神经元丢失最少.结论亚低温对癫痫大鼠有脑保护作用.     

蛇床子素对癫痫大鼠电压门控钾通道Kv1.2表达的影响

目的通过检测大鼠海马区钾通道Kv1.2蛋白表达的差异,探讨蛇床子素(osthole,OST)对海人酸(KA)致痫大鼠神经元的保护作用及其机制。方法 60只SD雄性大鼠随机分成空白对照组、模型组、OST组各20只。OST组首先给予OST灌胃,对照组、模型组给予等量的生理盐水灌胃,10d后,OST组与模型组通过颈内皮下注射KA致痫,对照组经颈内皮下注射等量的生理盐水。用免疫组化法和Western blot方法检测大鼠海马CA3区瞬时外向钾离子通道Kv1.2蛋白表达。结果模型组大鼠海马CA3区Kv1.2蛋白表达水平低于空白对照组(P<0.05);OST组大鼠海马CA3区Kv1.2蛋白表达水平高于模型组(P<0.05);且与空白对照组比较无明显差异(P>0.05)。结论大鼠海马CA3区神经元Kv1.2表达减少与KA导致大鼠痫样发作有关;OST对KA致痫大鼠神经元有保护作用,其作用的发挥可能与OST可增加海马CA3区神经元Kv1.2的表达有关。     

γ-氨基丁酸能神经元在新生大鼠缺氧性痫性发作中的作用

目的 通过观察新生大鼠早期发育过程中及缺氧性痫性发作后海马组织病理改变以及原癌基因c-fos蛋白、谷氨酸脱羧酶(glutamate decarboxylase,GAD)的变化,探讨γ-氨基丁酸(γ-amino butylic acid,GABA)能神经元在缺氧性痫性发作中的作用及可能的影响机制.方法 采用出生后10d的SD大鼠建立改良Jensen缺氧诱导痫性发作模型,分为痫性发作后1d、3d、7d、14d 4组,并选取相应时间点正常大鼠为对照组,采用尼氏染色方法检测海马组织的组织病理变化,免疫组织化学法检测各组海马c-fos蛋白灰度值以及GAD阳性神经元数量的改变.结果 尼氏染色结果显示,各缺氧性痫性发作组海马区形态结构正常,细胞排列略稀疏,但未见明显的细胞丢失.免疫组化结果显示,与对照组比较,c-fos蛋白灰度值在痫性发作后7d,在缺氧性痫性发作组海马CA2、CA3和DG区明显地降低(P ＜0.05);GAD阳性细胞数在痫性发作后7～ 14d,缺氧性痫性发作组海马CA1、CA3和DG区明显地减少(P＜0.05).结论 缺氧性痫性发作后14d内并没有造成大鼠海马区及时或迟发性细胞丢失,但c-fos表达在大鼠海马区有迟发性增高;缺氧性痫性发作后海马GABA神经元数量的减少可能是新生大鼠缺氧诱导痫性发作后癫痫易感性升高的原因之一.     

白藜芦醇对戊四氮致痫大鼠脑脊液、血清S1OOB蛋白的影响

目的 研究白藜芦醇(Res)对戊四氮致痫大鼠脑脊液、血清S100B蛋白的影响.方法 采用戊四氮(PTZ)腹腔注射建立慢性癫痫模型,造模成功后予以Res(15 mg/kg·d)灌胃干预10 d;采用酶联免疫吸附法测定脑脊液、血清S100B蛋白含量,海马标本行Nissl染色.结果 经28 d连续给药,18只大鼠符合Racine点燃标准,Res干预组大鼠痫性发作潜伏期明显延长,且发作时间明显低于癫痫模型组、二甲基亚砜组(P＜0.05).海马Nissl染色提示Res干预对大鼠海马CA1、CA3区神经元有保护作用(P＜0.05),而对齿状回保护作用不明显(P＞0.05).Res干预组大鼠脑脊液、血清S100B蛋白含量低于癫痫模型组、二甲基亚砜组(P＜0.05).结论 Res降低PTZ致痫大鼠脑脊液、血清S100B蛋白含量,或许减缓癫痫发作脑损伤发挥神经保护作用.     

Hypoxia prevents seizures and neuronal damages of the hippocampus induced by kainic acid in rats

The effects of hypoxia on the epileptic seizures and neuronal damages induced by kainic acid were studied in rats using hypoxic chamber equipment. Rats treated with kainic acid and placed in atmospheric pressure showed typical limbic seizures and regressive neuronal changes in CA3 and CA4 of the hippocampus, while those kept in a hypoxic chamber with 8.5% O2 and 91.5% N2 showed moderate hypoxia and a slight decline of mean arterial blood pressure. In these hypoxic rats, seizures were completely prevented and there was remarkably less regressive neuronal injury of the hippocampus. Thus hypoxia has a rather ameliorative effect on the occurrence of seizures and excitotoxic neuronal injuries induced by kainic acid. The contribution of oxygen radicals and endogenous adenosine to preventing excitotoxic neuronal damages by kainic acid was discussed.     

癫痫发作大鼠海马神经元凋亡与caspase-3 mRNA表达的研究

目的 :研究癫大鼠海马神经元凋亡与caspase 3mRNA表达的关系。方法 :采用大鼠红藻氨酸 (KA)致模型 ,以原位末端标记 (TUNEL)检测癫后不同时间海马神经元凋亡 ;RT PCR检测caspase 3mRNA的表达。结果 :KA致后 1d ,海马CA1、CA3及CA4区开始出现凋亡细胞 ,3d时明显增多 ,7d时最多。KA致后 6h ,海马组织caspase 3mRNA表达显著增高 ,1、3、7d仍持续高水平表达。结论 :癫大鼠海马神经元凋亡与caspase 3mRNA的表达密切相关 ,caspase 3在神经元凋亡过程中起着重要的作用     

癫痫大鼠海马CA3区钙超载与癫痫发病机制的相关性研究

目的:探讨癫痫的发病机制,海马CA3区钙超载是否在癫痫的发病机制中起主要作用。方法:用荧光倒置显微镜来测定癫痫状态下海马CA1、CA3区钙超载的情况,并用钙离子拮抗剂尼莫地平作用于海马脑片看钙超载的变化。并把点燃成功的大鼠麻醉后做海马脑片,看海马的组织病理学改变。结果:癫痫大鼠海马CA1、CA3区钙超载高于对照组,CA3区钙超载高于CA1区,在尼莫地平的作用下CA3区钙超载明显降低。组织病理学改变亦显示CA3区是神经元变性、坏死是海马区最明显的部位。结论:钙超载参与了癫痫的发病机制,其中海马CA3区的钙超载在癫痫发病机制中起主要作用。     

Immunohistochemical investigation of voltage-gated potassium channel-interacting protein 1 in normal rat brain and Pentylenettrazole-induced seizures

1 Introduction To discover accessory subunit of the Kv4 A-type channel, three novel proteins termed Kv channel-interact- ing proteins were identified as KChIP1, KChIP2, and KChIP3, and another homologue KChIP4 was found latterly. These novel proteins turn out to have around 40% amino-acid similarity to neuronal calcium sensor-1 (NCS-1) and belong to neuronal calcium sensor (NCS) family, which consists of those EF-hand-containing Ca2 -binding pro- teins that express predominantly or …     

Immunohistochemical investigation of voltage-gated potassium channel-interacting protein 1 in normal rat brain and Pentylenettrazole-induced seizures

Objective To explore the possible role of voltage-gated potassium channel-interacting protein 1 （KChIP1） in the pathogenesis of epilepsy. Methods Sprague Dawley female adult rats were treated with pentylenettrazole （PTZ） to develop acute and chronic epilepsy models. The approximate coronal sections of normal and epilepsy rat brain were processed for immunohistochemistry. Double-labeling confocal microscopy was used to determine the coexistence of KChIP1 and gamma-aminobutyric acid （GABA）. Results KChIP1 was expressed abundantly throughout adult rat brain. KChIP1 is highly co-localize with GABA transmitter in hippocampus and cerebral cortex. In the acute PTZ-induced convulsive rats, the number of KChIP 1-postive cells was significantly increased especially in the regions of CA 1 and CA3 （P 〈 0.05）; whereas the chronic PTZ-induced convulsive rats were found no changes. The number of GABA-labeled and co-labeled neurons in the hippocampus appeared to have no significant alteration responding to the epilepsy-genesis treatments. Conclusion KChIP1 might be involved in the PTZ-induced epileptogenesis process as a regulator to neuronal excitability through influencing the properties of potassium channels. KChIP1 is preferentially expressed in GABAergic neurons, but its changes did not couple with GABA in the epileptic models.     

Activation of Rho after traumatic brain injury and seizure in rats

Traumatic brain injury (TBI) is characterized by a progressive cell loss and a lack of axonal regeneration. In the central nervous system (CNS), the Rho signaling pathway regulates the neuronal response to growth inhibitory proteins and regeneration of damaged axons, and Rho activation is also correlated with an increased susceptibility to apoptosis. To evaluate whether traumatic brain injury (TBI) results in changes in Rho activation in vulnerable regions of the brain, GTP-RhoA pull down assays were performed on rat cortical and hippocampal tissue homogenates obtained from 24 h to 3 days following lateral fluid percussion brain injury (FPI). Following FPI, a significantly increased RhoA activation was observed from 24 h to 3 days post-injury in the cortex and by 3 days in the hippocampus ipsilateral to the injury. We also detected activated RhoA in the cortex and hippocampus contralateral to the injury, without concomitant changes in total RhoA levels. To determine if immediate post-traumatic events such as seizures may activate Rho, we examined RhoA activation in the brains of rats with kainic acid-induced seizures. Severe seizures resulted in bilateral RhoA activation in the cortex and hippocampus. Together, these results indicate that RhoA is activated in vulnerable brain regions following traumatic and epileptic insults to the CNS.     

Prolonged low-dose caffeine exposure protects against hippocampal damage but not against the occurrence of epilepsy in the lithium-pilocarpine model in the rat

PURPOSE: Acute caffeine exposure has proconvulsant effects and worsens epileptic and ischemic neuronal damage. Surprisingly, prolonged caffeine exposure decreases the susceptibility to seizures and the extent of ischemic damage. We explored whether the exposure to a low long-term dose of caffeine could protect the brain from neuronal damage and epileptogenesis in the lithium-pilocarpine model of temporal lobe epilepsy. METHODS: Rats received either plain tap water or water containing caffeine (0.3 g/L) for 15 days before the induction of status epilepticus (SE) by lithium-pilocarpine and for 7 days after SE. The extent of neuronal damage was assessed in the hippocampus and piriform and entorhinal cortices in brain sections stained with thionine and obtained from animals killed 7 days after SE. The latency to spontaneous recurrent seizures was controlled by video monitoring. RESULTS: Caffeine treatment induced a marked, almost total neuroprotection in CA1 and a very limited protection in the hilus of the dentate gyrus, whereas damage in layers III-IV of the piriform cortex was slightly worsened by the treatment. All rats, whether they received caffeine or plain tap water, became epileptic after the same latency (17-19 days). CONCLUSIONS: Thus these data extend the neuroprotective effects of low long-term caffeine exposure to epileptic damage and confirm that the sole protection of the Ammon's horn has no influence on the genesis of spontaneous recurrent seizures in this model.     

Neuropathology of the chronic epileptic syndrome induced by intrahippocampal tetanus toxin in rat: preservation of pyramidal cells and incidence of dark cells

A few nanograms of tetanus toxin injected into a rat hippocampus causes a chronic epileptic syndrome characterized by brief seizures that recur intermittently for about 6 weeks. Cognitive and other behavioural impairments persist after the seizures and other epileptic electrographic activity have remitted, and may be permanent. Our previous studies suggested that the behavioural changes following seizure remission were an indication of functional impairment associated with decreased neuronal excitability rather than with neuronal loss. The conclusion that neurons were preserved relied on qualitative histological observations and, indirectly, on electrophysiological measurements of the amplitudes of antidromic population spikes. Recently, gross histopathology has been described in a quantitative histological study of rats 7-10 days after they had received rather higher doses of intrahippocampal tetanus toxin. Here we report a quantitative histological study of hippocampi from rats which had gained remission from seizures induced by low doses of tetanus toxin. Adult Sprague Dawley rats received unilateral injections of 3-4 ng (about 6-8 mouse LD50) tetanus toxin, or vehicle, into the dorsal hippocampus. The first experiment confirmed that postsynaptic evoked responses recorded from pyramidal cells were depressed 10-19 weeks after injection. Unexpectedly, there also was a decrease of 20% in the antidromic response from CA3a contralateral to the injection. However, cell counts in these hippocampi revealed no change in pyramidal cell numbers. The second experiment used rats from two breeding colonies, prepared for histology 7 weeks after injection. Hippocampal pyramidal cell numbers were within the normal range in all but three of the 24 rats that had received tetanus toxin. These three had lesions of the CA1 pyramidal layer contralateral to the injection. The lesions were of the order of 2 mm in diameter, and were associated with glial proliferation. When these three cases were excluded, there remained a small increase in glial density in CA1 of the toxin-injected rats. In addition, toxin-injected rats from one of the colonies were susceptible to a pathology known as acidophylic or dark cell change. These occurred in 11 of 18 toxin-injected rats from this colony, in all divisions of the pyramidal layer, in both the injected and the contralateral hippocampus (where parallel studies revealed independent secondary epileptic foci). We conclude that loss of pyramidal neurons is not necessary for the persistent behavioural changes in this model.(ABSTRACT TRUNCATED AT 400 WORDS)