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.     

丝裂原活化蛋白激酶ERKs和JNKs在脑缺血损伤中的差异激活及其调控机制

目的　探讨丝裂原活化蛋白激酶家族 (MAPK)两成员ERK1/2和JNK1/2在全脑缺血损伤中的激活及其可能的分子机制。 方法　 采用四动脉结扎模型诱导SD大鼠前脑缺血 ,免疫印迹的方法观察ERK1/2和JNK1/2蛋白激酶特异性Thr和Tyr双位点磷酸化的变化及NMDA受体选择性拮抗剂对其双磷酸化的影响。结果　 缺血诱导海马脑区MAPK家族蛋白激酶两成员显著去磷酸化 ,严重缺血 (30min)ERK1/2而不是JNK1/2活性反弹 ;缺血再灌注ERK1/2活性在 15min首先升至最高而JNK1/2 1h后才逐渐升至峰值 (P <0 .0 5 ) ,2 4h再灌注能诱导两者的再次激活 ,且氯胺酮能显著抑制缺血诱导的ERK1/2而不是JNK1/2的激活。 结论　 前脑缺血明显诱导ERK1/2和JNK1/2的差异激活 ,提示两者可能分享不同的分子机制 ,其中ERK1/2的激活明显与NMDA受体功能上调有关。     

红藻氨酸诱导癫痫大鼠前脑CX32的表达及辛醇干预的影响

目的 观察红藻氨酸(kainic acid,KA)诱导癫痫大鼠前脑缝隙连接蛋白32(connexin 32,CX32)的表达及辛醇干预的影响.方法 用免疫荧光法检测癫痫发作后各时间点大鼠皮质及海马CX32阳性细胞表达.同时观察致痫前给予辛醇干预对大鼠皮质及海马CX32阳性细胞表达的影响.结果 KA致痫组大鼠皮层及海马CX32阳性细胞在各时程明显高于正常对照组(P<0.05),并且随时程延长呈增加趋势,7d达高峰,在海马中的变化比皮层明显,但无统计学意义(P>0.05).辛醇干预组大鼠皮层及海马CX32阳性细胞在各相应时程明显低于KA致痫组(P<0.01).结论 CX32组成缝隙连接(gap junction,GJ)在癫痫的发生发展过程中起重要作用,辛醇可以减少癫痫大鼠CX32表达,降低癫痫敏感性,实现脑保护作用.     

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。     

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。     

大鼠杏仁核电刺激癫痫模型海马JNK的磷酸化改变

目的 研究大鼠杏仁核电点燃癫痫模型海马中JNK的磷酸化改变,探讨JNK磷酸化与癫痫发生发展的关系.方法 建立大鼠杏仁核电点燃癫痫模型.设立空白对照组、手术对照组、点燃组,癫痫点燃成功后取脑,分别采用Western blot和免疫荧光方法 检测海马中JNK的表达变化,采用TUNEL染色和GFAP免疫组化染色观察海马形态学改变.结果 36只大鼠在12-20 d成功点燃.Western blot显示点燃组磷酸化JNK水平较手术对照组和空白对照组高(P<0.05).形态学检测显示点燃组海马区神经元缺失及神经胶质细胞增生(P<0.05).结论 电刺激诱发大鼠癫痫发作后,海马组织JNK磷酸化水平升高,该信号通路的激活可能参与颞叶内侧癫痫海马硬化的发生过程.     

抑制p38 MAPK信号通路对海马神经元毒性损伤的保护作用

目的通过观察细胞表面形态的三维构像变化,探讨抑制p38 MAPK通路对减轻红藻氨酸(KA)毒性作用引起大鼠海马神经元所造成损害的作用和机制。方法原代培养10 d的海马神经元给予SB203580(0.2μmol/L),p38MAPK特异性抑制剂)预处理.30min后再予不同浓度(0μmol/L,25μmol/L和250μmol/L)KA分别作用10 min和100 min,利用原子力显微镜(AFM)对细胞表面结构进行纳米级水平扫描和观测。结果正常海马神经元表面光滑,起伏均匀、规律;KA作用后神经元呈退行性改变,表现为胞体肿胀,胞膜表面粗糙,出现隆起和“孔洞”样胞膜破裂结构,并且其变化程度分别与作用时间和KA浓度呈量-效关系;预先给予SB203580处理,以上变化有所减轻。结论KA毒性作用后海马神经元胞膜表面超微结构所产生明显变化;p38MAPK信号通路参与这种损害过程;抑制该信号转导通路,对海马神经元的毒性损害起一定保护作用。     

α-硫辛酸对电点燃致痫大鼠行为学及海马p38MAPK表达的影响

目的探讨α-硫辛酸(α-LA)对电点燃致痫大鼠行为及海马p38MAPK表达的影响。方法将雄性Wistar大鼠随机分为正常对照组、α-LA组、假手术组、ES组、电低α-LA组、电高α-LA组。检测点燃前、后发放阈值(ADT)及达到每个发作等级所需的累积刺激数和累积后发放持续时间(ADD),应用Western blot检测海马p38MAPK及p-p38MAPK表达水平,碘化丙啶(PI)染色检测海马神经元凋亡率。结果与ES组相比:电高α-LA组达到第一次Ⅴ级发作所需的累积电刺激数明显增多(P<0.05)、点燃后ADT明显增高(P<0.05);电低α-LA组和电高α-LA组海马p-p38MAPK表达水平和神经元凋亡率明显降低(P<0.05)、达到第一次Ⅴ级发作所需的累积ADD明显缩短(P<0.05)。各组点燃后ADT较点燃前均明显降低(P<0.05)。结论癫痫可导致海马组织中pp38MAPK表达上调、神经元凋亡率明显增加;α-LA能够有效降低癫痫发作等级、缩短ADD、下调p-p38MAPK表达水平并降低神经元凋亡率,从而推测α-LA可通过抗凋亡途径来发挥神经保护作用。     

癫痫幼鼠海马丝裂酶原蛋白活化激酶表达的特点及其对巨噬细胞炎性蛋白-α/趋化因子受体5表达的影响

目的探讨癫痫幼鼠海马丝裂酶原蛋白活化激酶(MAPKs)表达的特点及其对巨噬细胞炎性蛋白-α(MIP-1α)/趋化因子受体5(CCR5)表达的影响。方法应用立体定向技术对侧脑室内注射海人酸(KA),建立幼鼠惊厥模型。将出生21 d的Wistar幼鼠分为空白对照组、磷酸盐缓冲液(PBS)对照组及KA 4h、8 h、16 h、24 h、3 d组,比较各组MAPKs表达的差异。另将出生21 d的幼鼠分为PBS+二甲亚砜(DMSO)组、KA+DMSO组、KA+PD98059(ERK1/2抑制剂)组和KA+SB203508(p38MAPK抑制剂)组,比较各组MIP-1α、CCR5表达的差异。采用Western Blot方法检测MAPKs蛋白水平及CCR5的表达。采用ELISA方法检测MIP-1α的表达。采用免疫组化染色方法检测各组大鼠海马P-ERK1/2、P-p38MAPKs等蛋白的表达。采用免疫荧光双标染色探讨P-ERK1/2和P-p38MAPK的胶质细胞来源。结果与空白对照组比较,KA 4 h、8h、16 h、24 h、3 d组P-ERK1/2水平明显增高;KA 8 h、16 h、24 h、3 d组P-P38MAPK水平明显增高(均P0.05)。侧脑室注射KA后大鼠P-ERK1/2与P-P38MAPK表达主要分布在齿状回门区和锥体细胞层等神经元损伤明显的海马组织中。在侧脑室注射KA后,部分P-ERK1/2来源于活化的小胶质细胞及星形胶质细胞,而P-p38MAPK仅在小胶质细胞中出现免疫活性表达。与PBS+DMSO组比较,KA+DMSO组、KA+PD98059组和KA+SB203508组大鼠海马组织中MIP-1α、CCR5蛋白水平均明显增高,OX-42阳性细胞数明显增加(均P0.05)。与KA+DMSO组比较,KA+PD98059组、KA+SB203508组大鼠海马组织中MIP-1α、CCR5蛋白水平均明显降低,OX-42阳性细胞数明显减少(均P0.05)。结论在幼鼠癫痫发生的早期阶段,MAPKs(ERK1/2、p38MAPK)可部分地调控MIP-1α/CCR5的表达。     

小剂量3-NPA对KA致痫大鼠海马神经细胞凋亡和p53蛋白表达的影响

目的探讨小剂量线粒体毒素3-硝基丙酸（3-NPA）预处理对红藻氨酸（KA）致痫大鼠海马神经细胞凋亡和p53蛋白表达的影响.方法大鼠腹腔注射20 mg/kg 3-NPA（4 mg/mL）或生理盐水后24 h制作大鼠癫痫模型及对照模型,7 d后分别用原位末端标记（TUNEL）法、免疫组织化学方法观察小剂量3-NPA预处理对KA致痫大鼠海马CA1区神经细胞凋亡和P53蛋白表达的影响. 结果3-NPA预处理组较对照组CA1区神经细胞凋亡减少,p53蛋白表达减弱. 结论小剂量3-NPA预处理可以对KA致痫大鼠海马神经细胞凋亡和p53蛋白表达有抑制作用,3-NPA预处理可能对KA致痫大鼠海马细胞凋亡具有一定保护作用.     

Inhibition of delayed induction of p38 mitogen-activated protein kinase attenuates kainic acid-induced neuronal loss in the hippocampus

The activation of p38 mitogen-activated protein kinase (MAPK) has been implicated in the pathological changes accompanying inflammatory and apoptotic processes of various cell types including neurons. In a kainic acid (KA)-induced mouse seizure model, p38 MAPK is induced in reactive astrocytes in the CA3 region of the hippocampus where severe neuronal loss occurs. Here we report the delayed and protracted activation of p38 MAPK in the CA3 region of the hippocampus of mice treated with KA. In this model, the inhibition of p38 MAPK isoforms by SB203580, a specific inhibitor, attenuated neuronal loss in the CA3 and CA1 regions of the hippocampus, which was accompanied by the suppression of the p38 MAPK activation as well as astrogliosis. Thus, the delayed and sustained induction of p38 MAPK plays a crucial role in the neuronal damage of KA-induced brain seizures.     

Delayed induction of p38 MAPKs in reactive astrocytes in the brain of mice after KA-induced seizure

Activation of p38 mitogen-activated protein kinase (p38 MAPK) has been implicated in pathological changes in inflammatory and apoptotic processes in various cell types including neurons. Here we report the delayed induction of p38 MAPKs in the brain of mice following kainic acid (KA)-induced seizure. The immunoreactivities of p38alpha and p38beta MAPKs were markedly increased in the brain 4 days after KA administration, especially in the areas undergoing selective neuronal loss. In particular, p38beta was dramatically increased in reactive astrocytes of CA3 and CA1 regions of hippocampus with its enriched localization in the nucleus of astrocytes. The induction of p38beta was sustained for more than 10 days after KA-treatment. Pre-administration of the selective neuronal nitric oxide synthase (nNOS) inhibitor, 7-nitroindazole (7-NI), which suppressed the delayed neuronal death as well as astrogliosis in hippocampus of seizure-experienced animals, dramatically repressed the delayed induction of p38beta MAPK in astrocytes. The repression was reversed by the co-injection with L-arginine (L-arg), a substrate for NOS, which coincided with the aggravation of neuronal death. Together, these data suggested a role of p38 MAPK signal pathway in delayed neuronal death and/or in reactive gliosis in mice with KA-induced seizure.     

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.     

Secondary Generalization in Kainic Acid-Induced Focal Seizures in Unanesthetized Cats

Abstract: Seizure propagation was studied with different seizure models induced by a kainic acid (KA) microinjection in nonanesthetized cats. These seizures were characterized with a focal onset of seizures followed by secondarily generalized seizures. The mesencephalic reticular formation (MRF) played an important role when an epileptogenic focus was located in a unilateral amygdala, hippocampus, thalamus or visual cortex. When the focus was located in a unilateral lateral geniculate body, a fast, synchronous and bidirectional propagation was observed in the sensorimotor cortex (SMC) and MRF. Brain stem seizure (generalized tonic seizure) was elicited by the KA injection into MRF. The EEG of generalized seizure was characterized by the propagations of seizure activities of MRF immediately to the bilateral SMC and thalamus. The results suggested that MRF participated actively in the generalization of the KA-induced seizures .     

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。     

Synergistic action of corticosterone on kainic acid-induced electrophysiological alterations in the hippocampus

The present study investigates the effect of overexposure to high doses of the stress hormone corticosterone (CORT) on the electrophysiological changes produced in the hippocampus after local microinjection of KA. Extracellular recordings were performed in the CA1 area of mouse hippocampal slices prepared after a 7-day recovery period following KA microinfusion alone or combined with 3 days overexposure to CORT. The results showed that CORT shifts the KA response profile approximately 40-fold, since animals treated with a non-toxic dose of 0.01 μg KA and CORT exhibited epileptic activity and a shift on the paired-pulse response similar to that observed in animals treated with high doses of KA (0.4 μg). This synergistic action of CORT on the electrophysiological changes induced by KA was antagonized by the antiglucocorticoid RU486 whereas the antimineralocorticoid spironolactone was ineffective. These results suggest that CORT may play an important role in modulating the severity of KA-induced seizures in the hippocampal structure probably by GR-receptor mediated action.     

红藻氨酸致痫大鼠海马Fos和GFAP的共同表达

目的 研究红藻氨酸（kainic acid,KA)诱导大鼠癫痫发作后海马（hippocampus,HI)内神经元和星形胶质细胞的时空效应性反应变化。方法 大鼠侧脑室内注射KA，用抗即刻早期基因Fos蛋白和抗胶质原纤维酸性蛋白（GFAP）的双重免疫荧光组织化学方法结合激光共聚焦显微镜技术，显示痫性发作后HI同一部位内反应性神经元与星形胶质细胞的分布。结果 KA诱导大鼠癫痫发作，HI内的Fos阳性神经元和GFAP阳性星形胶质细胞明显增多。两分布范围基本一致，且癫痫诱发30min后GFAP开始增多，1h达高峰；1h后Fos阳性产物开始增多；2h达高峰；部分Fos阳性神经元周围有GFAP免疫反应产物包绕，显示反应性神经元（Fos阳性）与反应性星形胶质细胞（GFAP阳性）之间关系密切。结论 HI内的神经元和星形胶质细胞与癫痫发作直接相关且存在相互关系。可能共同参与癫痫的发生及其调节。     

胶质细胞源性神经营养因子在大鼠急性痫性发作中的表达

目的动态观察胶质细胞源性神经营养因子（GDNF）蛋白在红藻氨酸（KA）诱导的大鼠急性痫性发作中的表达水平,探讨GDNF在急性癫痫发作中的作用。方法成年SD大鼠随机分为NS对照组和KA处理组。急性痫性发作经单侧海马内注入KA(0.6μg/0.3μl)诱导。两组大鼠分别在注射后第3、6、24h和第4、7d,采用免疫细胞化学方法检测GDNF蛋白在海马中的表达水平。结果NS组海马GDNF表达极微量,各时间点均在基线水平。KA组在注射后3hGDNF少量增高,6h达高峰,并持续至第4d,均高于各时间点NS组（P<0.05）,至第7d回复正常水平（P>0.05）。双侧GDNF表达在各时间点无显著差异。结论单侧海马内注射KA诱导的大鼠急性痫性发作可导致双侧海马齿状回和门区GDNF蛋白表达增高,GDNF可能参与拮抗KA神经兴奋性毒性作用,对海马齿状回颗粒细胞起保护效应。