杏仁核内注射KA诱导的边缘叶发作大鼠海马中caspase-9的表达

目的 :红藻氨酸 (kainicacid ,KA)诱导的大鼠边缘叶发作模型 ,检测半胱氨酸天冬酶 9(caspase 9)在癫大鼠海马神经元表达。方法 :立体定位杏仁核注射KA诱导癫发作 ,以持续记录脑电、局部脑血流 (regionalcerebralbloodflow ,r CBF) ,用TUNEL染色和cresylviolet染色观察海马神经元存活和凋亡 ;用免疫荧光和Westernblot检测海马caspase 9的表达。结果 :发作终止 4h时caspase 9出现裂解片段 ,8h时出现TUNEL阳性细胞 ,2 4h时达高峰。脑室内注射caspase 9抑制剂z LEHD fluoromethylketone(z LEHD fmk)可减少TUNEL阳性细胞 ,增加存活神经元 ;发作后在KA注射同侧海马的CA3区神经元caspase 9免疫反应性增强 ;对侧海马未见TUNEL阳性细胞及caspase 9的上述变化。发作前后r CBF无明显变化。结论 :癫发作可诱导caspase 9的激活。caspase 9可能是癫潜在的治疗靶点。     

雌激素影响海人酸杏仁核点燃大鼠癫(癎)发作机制的初步探讨

目的:探讨雌激素(E)和姜黄素(C)影响癫发作的机制。方法:用E和C单独及联用连续处理去势雌性大鼠5d,第6天以海人酸(KA)杏仁核点燃法制备癫大鼠模型,观察大鼠癫发作的行为学表现,用免疫组化方法检测海马组织c-Jun蛋白的表达。结果:E加C组(EC KA组)大鼠癫重度发作的严重程度较E组(E KA组)明显减轻(P<0.05)。E KA组海马中c-Jun蛋白表达最多,C组(C KA组)及对照组(KA组)均表达较少且没有任何差异;EC KA组海马的CA1区c-Jun蛋白表达较E KA组明显减少(P<0.05)。结论:C能一定程度上减轻E引起的癫发作加重,它可能通过抑制c-Jun/核转录因子激活蛋白-1(activate-protein1,AP-1)活性,使E作用的AP-1通路受阻,从而减轻了E的促神经元兴奋作用。     

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.     

海藻氨酸致癫痫状态大鼠海马区神经元损伤与Mg^2＋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.     

红藻氨酸诱导癫(癎)发作大鼠海马星形胶质细胞C-FOS基因表达的研究

目的研究癫发作大鼠海马星形胶细胞C-FOS基因表达的变化,探讨其对癫发作的维持与复发的影响。方法将83只成年雄性SD大鼠随机分为实验组58只,对照组25只。实验组在海马CA3区注射红藻氨酸(Kainicacid,KA)建立癫模型,对照组在相同部位注射等量生理盐水。利用免疫组织化学双重染色技术,分别在癫发作后1h、3h、6h、12h和24h观察大鼠海马星形胶质细胞C-FOS基因的表达。结果与对照组大鼠比较,癫模型鼠海马CA1区CFAP/C-FOS双标记阳性细胞百分率于癫发作后1h(12.70±0.03)、3h(17.10±0.05)、6h(24.92±0.04)明显升高(P<0.01),在6h达到高峰,在12h下降,但是仍较对照组高(10.71±0.06;1.59±0.02,P<0.01),在24h下降至对照组水平(2.00±0.02;2.08±0.03,P>0.05)。结论KA诱导大鼠癫发作,导致海马星形胶质细胞C-FOS基因相对持续的高表达,从而激活星形胶质细胞,产生高致性的病理环境,可能是癫发作的维持以及复发的病理生理机制之一。     

辛醇预处理对红藻氨酸诱导的癫(癎)大鼠海马神经元凋亡和胶质纤维酸性蛋白表达的影响

目的 观察缝隙连接阻断剂辛醇预处理对红藻氨酸(KA)诱导的癫(癎)大鼠海马神经元凋亡和胶质纤维酸性蛋白(GFAP)表达的影响.方法 160只雄性SD大鼠随机分为KA组、辛醇组、生理盐水(NS)组和二甲基亚砜(DMSO)组,应用KA右侧杏仁核注射制作癫(癎)大鼠模型;制模前30 min辛醇组腹腔注射辛醇溶液;制模后3h、6h、12 h、24 h和7d应用原位末端标记(TUNEL)法和免疫组化染色法分别检测各组大鼠海马CA3区TUNEL和GFAP阳性细胞数.结果 KA组制模后6h海马CA3区有TUNEL阳性细胞表达,并逐渐增多,7d达高峰;辛醇组制模后在6 h～7 d TUNEL阳性细胞数明显少于KA组(均P＜0.01);KA组海马CA3区GFAP阳性细胞数随时间而逐渐增多,各时间点明显多于辛醇组(均P＜0.01).结论 辛醇神经保护作用的机制可能与抑制细胞缝隙连接间通讯,切断凋亡信号传播,以减少神经元凋亡有关.     

辛醇预处理对红藻氨酸诱导的癫疒间大鼠海马神经元凋亡和胶质纤维酸性蛋白表达的影响

目的观察缝隙连接阻断剂辛醇预处理对红藻氨酸(KA)诱导的癫疒间大鼠海马神经元凋亡和胶质纤维酸性蛋白(GFAP)表达的影响。方法 160只雄性SD大鼠随机分为KA组、辛醇组、生理盐水(NS)组和二甲基亚砜(DMSO)组,应用KA右侧杏仁核注射制作癫疒间大鼠模型;制模前30 min辛醇组腹腔注射辛醇溶液;制模后3 h、6 h、12 h、24 h和7 d应用原位末端标记(TUNEL)法和免疫组化染色法分别检测各组大鼠海马CA3区TUNEL和GFAP阳性细胞数。结果 KA组制模后6 h海马CA3区有TUNEL阳性细胞表达,并逐渐增多,7 d达高峰;辛醇组制模后在6 h～7 d TUNEL阳性细胞数明显少于KA组(均P<0.01);KA组海马CA3区GFAP阳性细胞数随时间而逐渐增多,各时间点明显多于辛醇组(均P<0.01)。结论辛醇神经保护作用的机制可能与抑制细胞缝隙连接间通讯,切断凋亡信号传播,以减少神经元凋亡有关。     

癫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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持续状态大鼠模型。Nissl染色观察癫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持续状态组相比,癫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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持续状态前,以及癫持续状态后6、12、24 h均高于癫持续状态组(均P=0.000),至第2和7天时与癫持续状态组之间差异无统计学意义(P0.05)。结论经2-脱氧葡萄糖诱导的内质网应激预适应对癫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。     

米诺环素对戊四氮致疒间大鼠海马神经元凋亡的保护作用

目的探讨米诺环素对神经元凋亡的保护作用及与剂量的关系。方法采用戊四氮(PTZ)建立的癫疒间大鼠模型,用灌胃法给不同剂量的米诺环素后麻醉大鼠,灌注取脑进行石蜡切片制备及免疫组化检测,采用HPIAS-1000高清晰度彩色病理图文分析系统进行图像分析,观察大鼠海马区细胞凋亡变化。结果对照组与PTZ组比较,对照组凋亡数目少(P<0.05);MT1组与PTZ组比较,细胞凋亡无差异(P﹥0.05);MT2组与PTZ组比较,MT2组细胞凋亡数少(P<0.05);MT3组与PTZ组比较,MT3组细胞凋亡多(P<0.05)。各干预组之间比较,MT2组细胞凋亡较MT3组、MT1组都少(P<0.05)。结论米诺环素在适当的浓度范围内有神经元保护作用。     

红藻氨酸诱导的大鼠癫痫模型中海马神经元caspase-9活性的变化

目的 :观察红藻氨酸 (kainicacid ,KA)诱导的癫大鼠海马神经元caspase 9活性的变化。方法 :应用KA腹腔注射诱导大鼠癫模型 ,检测癫大鼠海马神经元caspase 9的活性。caspase 9活性的测定采用荧光底物分析法。结果 :注射KA后 1h大鼠海马神经元caspase 9活性开始升高 ,但与对照组相比 ,无统计学差异 ;注射KA后 3h大鼠海马神经元caspase 9活性达到高峰 ,与对照组相比P <0 0 5 ;然后开始下降 ,于注射KA后 12h接近于正常对照组水平。结论 :在KA腹腔注射诱导的大鼠癫模型中 ,海马神经元caspase 9活性仅在早期表达升高 ,提示caspase 9活性升高可能启动了癫大鼠海马神经元的损伤     

The protective effect of a ketogenic diet on kainic acid-induced hippocampal cell death in the male ICR mice

This study was designed to evaluate the antiapoptotic effects of a ketogenic diet (KD) through histological (cresyl violet staining, TUNEL staining and immunohistochemistry) and behavioral studies using kainic acid (KA, 25mg/kg i.p.)-induced seizures in male ICR mice. KA-induced seizure in rodents is widely used as an experimental model for human temporal lobe epilepsy because of their behavioral and pathological similarities. A KA-induced seizure causes neuronal damage in hippocampal pyramidal neurons and involves a caspase-3-mediated apoptotic pathway. In this study, the seizure onset time of the KD-fed group was delayed compared to that of the group fed a normal diet (ND) after a systemic KA injection. Histological studies revealed that KA caused pyknosis in most of the hippocampal areas in the ND-fed group, however, well-preserved pyramidal neurons were detected in the hippocampus of mice that had been on KD for 1 month, which began on postnatal day 21. The number of TUNEL-positive cells and caspase-3-positive cells in the hippocampus of the KD-fed group was lower than that of the ND-fed group. These findings indicate that KD has an antiepileptic effect via a neuroprotective action that involves the inhibition of caspase-3-mediated apoptosis of hippocampal neurons.     

致痫后雌性大鼠血清及海马雌二醇和孕烯醇酮水平的动态变化

目的 观察致病后雌性大鼠血清及海马雌二醇(E2)和孕烯醇酮(PREG)水平的动态变化,研究海马E2水平与癫痫发作严重程度的关系. 方法 选择动情期雌性大鼠制备海人藻酸(KA)经杏仁核点燃的癫痫模型,观察大鼠癫痫发作的行为学表现.应用放射免疫法和酶联免疫吸附分析分别检测癫痫发作后0、1、2、3、4、5、6、12和24 h的大鼠以及经杏仁核注射生理盐水后相应时间的大鼠血清及海马组织E2和PREG水平.对检测结果进行统计学分析. 结果 杏仁核注入KA后5～10min大鼠均出现痫样发作,3 h达峰值,随后呈下降趋势.致痫后的大鼠血清E2水平无明显变化,但海马E2水平在癫痫发作后1 h开始上升,4 h达峰值,随后呈下降趋势,12 h恢复至对照水平,1～12 h相邻时间点E2水平差异均有统计学意义(P,0.05).此外,随着大鼠的癫痫发作程度的加重,海马E2水平逐渐升高,进行相关性检验后发现.海乌E2水平与癫痫发作严重程度呈正相关(R~2=0.646,P<0.05).致痫前及致痫后24 h内不同时间点各组大鼠海马的PREG水平没有明显变化. 结论 癫痫发作后大鼠海马E2水平的动态变化与癫痫发作程度相关.癫痫发作可以诱导大鼠海马局部E2的合成.     

Age-dependent cyclooxygenase-2 induction and neuronal damage after status epilepticus in the postnatal rat hippocampus

PURPOSE: Epileptic seizures lead to age-dependent neuronal damage in the developing brain, particularly in the hippocampus, but the mechanisms involved have remained poorly elucidated. In this study, we investigated the contribution of apoptosis and inflammatory processes to neuronal damage after status epilepticus (SE) in postnatal rats. METHODS: SE was induced by an intraperitoneal injection of kainic acid (KA) in 21- and 9-day-old (P21 and P9) rats. The expression of Bax, Bcl-2 and caspase-3, markers for apoptosis, and cyclooxygenase-2 (COX-2), an indicator for activation of inflammatory processes, were studied from 6 h up to 1 week after SE by Western blotting and immunocytochemistry. Neuronal damage was verified by Fluoro-Jade B staining. RESULTS: In P21 rats, SE resulted in neuronal damage in the CA1 neurons of the hippocampus. COX-2 expression was extensively, but transiently, increased and its immunoreactivity pronouncedly enhanced in several hippocampal subregions, amygdala, and piriform cortex by 24 h after SE. The expression of Bax and caspase-3 remained unchanged, whereas the antiapoptotic factor Bcl-2 transiently decreased by 24 h. Single caspase-3 positive neurons appeared in the CA1 region of both control and KA-treated rats. In P9 rats, no neuronal death was detected, and COX-2 expression and immunoreactivity remained at the control level. DISCUSSION: Our results suggest that SE provokes age-specific effects on COX-2 expression. This together with the activation of putative inflammatory processes may contribute to neuronal cell death in the hippocampus of postnatal rats, whereas caspase-dependent apoptosis seems not to be involved in the death process.     

The effect of ischemic post-conditioning on hippocampal cell apoptosis following global brain ischemia in rats

We evaluated the effect of brain ischemic post-conditioning on cell apoptosis in the hippocampus following global brain ischemia in rats. Adult male Sprague-Dawley rats were randomly divided into three groups (n=15/group): sham operation, ischemia/reperfusion (I/R) and ischemic post-conditioning (I PostC). Global brain ischemia was induced by four-vessel occlusion. Ischemic post-conditioning consisted of six cycles of 10s/10s reperfusion/reocclusion at the onset of reperfusion. All rats were sacrificed 24 hours or 72 hours after reperfusion. The hippocampal CA1 regions were analysed using the terminal deoxynucleotidyl transferase-mediated biotinylated deoxyuridine triphosphate nick end-labelling (Tunel) staining technique for determining cell apoptosis. Levels of caspase-3 and Bcl-2 were measured by Western blotting. After 72 hours, fewer Tunel-positive brain cells were observed in rats from the I PostC group than in rats from the I/R group (10.3 ± 2.7% versus 40.8 ± 6.2%, p<0.01). After reperfusion at 24 hours and 72 hours, expression of caspase-3 in the I PostC group was significantly decreased (p<0.01) and expression of Bcl-2 in the I PostC group was significantly increased (p<0.01) compared with the I/R group. We conclude that down-regulation of caspase-3 and up-regulation of Bcl-2 by ischemic post-conditioning may underlie the protective effects of post-conditioning.     

Neuroprotection of co-activation of GABA receptors by preventing caspase-3 denitrosylation in KA-induced seizures

Previous studies have demonstrated that kainic acid (KA)-induced seizures can cause the enhancement of excitation and lead to neuronal death in rat hippocampus. Co-activation of the inhibitory GABA receptors can attenuate the excitatory JNK3 apoptotic signaling pathway via inhibiting the increased assembly of the GluR6-PSD-95-MLK3 signaling module induced by KA in epileptic rat hippocampal CA1 and CA3 regions. Caspase-3 is a cysteine protease located in both the cytoplasm and mitochondrial intermembrane space that is a central effector of many apoptotic pathways. We designed experiments to elucidate the underlying molecular mechanisms of procaspase-3 activation and neuroprotection of co-activation of GABA receptors against neuronal death induced by KA. In this study, we show that co-activation of GABA receptors can attenuate the Fas/FasL apoptotic signaling pathway and inhibit the increased of thioredoxin reductase activity induced by KA, subsequently inhibit the activation of procaspase-3 by diminishing the denitrosylation of its active-site thiol and decreasing the cleavage of the caspase-3 zymogen to its active subunits. These results indicate that co-activation of GABA receptors results in neuroprotection by preventing caspase-3 denitrosylation in KA-induced seizure of rats.     

Adiponectin protects hippocampal neurons against kainic acid-induced excitotoxicity

Neuronal damage after seizure is correlated with blood–brain barrier (BBB) leakage. Adiponectin (Ad) has shown protective effects on endothelial function. In this study, we investigated the effects of Ad on cell survival and BBB integrity in the mouse hippocampus after kainic acid (KA) treatment. Twenty-four hours after intracerebroventricular injection of recombinant Ad, mice were treated with KA, and then sacrificed 48 h later. Decreased serum Ad and increased hippocampal Ad receptor 1 in the hippocampus of KA-treated mice were prevented by Ad pretreatment. Using cresyl violet staining, TUNEL analysis, and immunostaining for caspase-3, histological evaluation revealed that the marked cell death noted in the hippocampus of KA-treated mice was not observed in KA-treated mice pretreated with Ad. Impairment of the BBB, which was demonstrated by the presence of IgG, was inhibited by Ad pretreatment. Immunohistochemical analysis indicated that KA caused up-regulation of hippocampal VEGF, eNOS, and NF-κB levels, all of which were reduced in animals that received Ad pretreatment. These data indicate that Ad preserves the integrity of the BBB and has neuroprotective effects in an animal model of seizures.     

Effects of topiramate on seizure susceptibility in kainate-kindled rats: involvement of peripheral-type benzodiazepine receptors.

This study was aimed to quantitatively evaluate the effects of topiramate (TPM) on seizure susceptibility and hippocampal peripheral-type benzodiazepine receptors (PBRs) in the kainic acid (KA) model of temporal lobe epilepsy. Male rats were randomized into saline control group, KA group, KA/TPM low dose group and KA/TPM high dose group. Three weeks after single injection of KA (10 mg kg(-1), sc), the effects of TPM were tested at two doses (10 and 30 mg kg(-1), sc) once a day for 1 week in KA/TPM low dose group or KA/TPM high dose group, respectively. Rats in KA group received comparable injections of saline. Four weeks after initial KA injection, a subconvulsant dose KA (5 mg kg(-1), sc) was administered in rats in these three groups. Rats in saline control group received equal volume of saline. All animals were decapitated and hippocampus synaptosomes were purified 180 min after behavioral observation. PBRs specific binding sites were assessed by an in vitro binding technique utilizing the highly selective ligand [(3)H]PK11195. Seizure threshold was elevated and specific PBRs binding in hippocampus was decreased by TPM in dose-dependent manner. Specific PBRs binding in hippocampus was significantly related to seizure latency and seizure intensity. These results suggest that TPM can reduce the susceptibility to seizures in KA-kindled rats and its anticonvulsant effect seems resulting from, at least in part, the reduced PBRs binding after treatment. These results also support the hypothesis that PBRs represent a novel target for antiepileptic drug development.     

红藻氨酸诱导大鼠癫痫发作的电生理机制研究

目的　探讨红藻氨酸 ( KA)诱导大鼠复杂部分性癫痫发作的 EEG特点以及可能的电生理起搏点位置。方法　在立体定位指引下 ,将 EEG记录电极植入 1 2只大鼠双侧海马、额叶皮质或杏仁核中 ,其中 8只为实验组 ,4只为对照组。手术后 1周在大鼠清醒状态下 ,连续描记 KA或盐水注射后 EEG 1 2 0 min,观察 EEG波形、波幅以及频率的变化特点并记录每次电发作的起搏点位置。结果　 ( 1 ) KA注射后大鼠 EEG表现出多种形式的放电波形 ,典型波形有单棘波、多棘波、多相棘波、正相棘波、棘节律、节律性慢波、棘慢波等。 ( 2 )大鼠在凝视发作以及自动症发作时海马、杏仁核和额叶皮质均有异常放电。 ( 3) KA注射后大鼠电发作起搏点不固定。 ( 4 )各导放电频率多数情况下一致 ,偶有不一致现象。 ( 5 )存在亚临床放电。结论　 ( 1 ) KA注射后大鼠 EEG表现为多种形式的电发作活动 ;( 2 )大鼠在复杂部分性发作过程中不仅有边缘系统参与 ,也有边缘外额叶皮质参与 ;( 3)KA模型中 ,电发作起搏点不固定 ,KA注射后大鼠脑内可能存在一个异常的神经元网络 ,在网络中存在放电不均衡现象。