大鼠颞叶癫痫点燃后海马zif268mRNA及其蛋白的时空表达变化

目的 探讨海马zif268mRNA及其蛋白的时空表达变化与颞叶癫痫脑损伤的关系. 方法 将雄性Wistar大鼠随机分为3组:其中正常组6只,假手术对照组(Sham组)和海人酸(KA)颞叶癫痫点燃组(TLE组)各36只,后两组按点燃后6h、24h、3d、7d、14d、21d时间点各分为6小组,每小组6只.采用KA杏仁核点燃建立经典颞叶癫痫模型,应用原位杂交和免疫组织化学方法分别检测海马神经元zif268mRNA及其蛋白的表达.结果 TLE组zif268mRNA表达在总体上和点燃后远期21d海马CA1、CA3区和齿状同(DG)均高于Sham组(P＜0.05).TLE组Zif268蛋白表达在总体上和远期21d海马DG表达低于Sham组(P＜0.05).回归分析提示颞叶癫痫与海马zif268mRNA表达呈正相关(β=0.286,P＜0.001),与Zif268蛋白表达呈负相关(β=-0.153,P＜0.001).结论 颞叶癫痫大鼠海马zif268mRNA及其蛋白的时空表达变化可能参与颞叶癫痫发病及其脑损伤过程.     

海人酸致痫大鼠海马结构GABAB受体亚单位表达的研究

目的：探讨海人酸诱导大鼠颞叶癫痫（EP）发作后2种γ-氨基丁酸（GABA）受体亚单位GABABR亚单位1a（GBR1a）和GABABR亚单位2（GBR2）在EP发生、发展中的作用。方法：运用原位杂交及免疫组化法，检测EP发作后GABABR亚单位mRNA及蛋白在海马的表达。结果：致痫早期CA1和CA3区2种亚单位mRNA表达持续低下后逐渐增加，DG区则暂时性下降后很快回升；而免疫反应早期却未见明显改变，随后CA1和CA3区表达处于低水平，DG区和颞叶皮质表达下降后很快恢复。结论：致痫后2种GABAB受体亚单位基因和蛋白表达上调为颞叶EP的内源性自我保护机制。     

海人酸癫痫大鼠模型的TNF-α及其mRNA表达特征

目的立体定向手术建立海人酸颞叶癫痫模型,检测癫痫大鼠海马内TNF-α及其mRNA的表达, 评价其意义。方法大鼠一侧海马CA3区注射海人酸,观察其行为学特征及HE染色的病理学改变,免疫组化和原位杂交法检测大鼠海马内TNF—α蛋白和mRNA的动态表达。结果大鼠注射海人酸后出现湿狗样抖动、头面部肌阵挛、肢体阵挛及全面强直阵挛发作等,病理可见海马神经元变性、缺失及胶质细胞增生,海马内TNF-α蛋白与 mRNA表达时程基本一致,3h出现,12h达高峰,而后逐渐下降,7d后回归至对照组表达水平,15d,30d又高于对照组。结论在一侧海马注射海人酸的大鼠癫痫模型中,内源性TNF—α参与了癫痫的发病机制。     

海人酸致大鼠海马结构GABA_B受体亚单位表达的研究

目的:探讨海人酸诱导大鼠颞叶癫(EP)发作后2种γ-氨基丁酸(GABA)受体亚单位GABABR亚单位1a(GBR1a)和GABABR亚单位2(GBR2)在EP发生、发展中的作用。方法:运用原位杂交及免疫组化法,检测EP发作后GABABR亚单位mRNA及蛋白在海马的表达。结果:致早期CA1和CA3区2种亚单位mRNA表达持续低下后逐渐增加,DG区则暂时性下降后很快回升;而免疫反应早期却未见明显改变,随后CA1和CA3区表达处于低水平,DG区和颞叶皮质表达下降后很快恢复。结论:致后2种GABAB受体亚单位基因和蛋白表达上调为颞叶EP的内源性自我保护机制。     

GAD在颞叶癫痫大鼠海马内源性促痫机制中的作用

目的:探讨GAD65、GAD67在颞叶癫痫发生后海马内源性促痫机制中的作用。方法:112只雄性SD大鼠随机分为实验组(n=70)与对照组(n=42),实验组大鼠选用海人酸腹腔注射法建立颞叶癫痫模型,对照组大鼠腹腔注射无菌生理盐水。选取腹腔注射后3小时、6小时、12小时、24小时、48小时、7天、30天为研究的时间点,颞叶海马的CA1区、CA3区、齿状回为研究部位。腹腔给药后每天观察大鼠的行为学变化,大鼠处死前进行EEG描记。用原位杂交方法检测不同时间点海马不同区域GAD65、GAD67mRNA的表达,免疫组织化学法检测GAD65、GAD67蛋白的表达。结果:实验组大鼠海马GAD65 mRNA及其蛋白的表达随时间呈逐渐增高趋势,致痫后48小时～30天,GAD65 mRNA及其蛋白表达较对照组增高(48小时P<0.05;7～30天P<0.01);海人酸致痫后6小时、24小时实验组大鼠海马的GAD67mRNA及其蛋白表达较对照组增高(分别为P<0.01、P<0.05)。结论:颞叶癫痫急性期海马GAD67表达的增高及慢性期海马GAD65表达的增高是癫痫发生后机体的内源性抗痫机制。     

海人酸致(癎)大鼠海马结构GABAB受体亚单位表达的研究

目的:探讨海人酸诱导大鼠颞叶癫(癎)(EP)发作后2种Y-氨基丁酸(GABA)受体亚单位GABAnR亚单位1a(GBRla)和GABABR亚单位2(GBR2)在EP发生、发展中的作用.方法:运用原位杂交及免疫组化法,检测EP发作后GABABR亚单位mRNA及蛋白在海马的表达.结果:致痫早期Cal和CA3区2种亚单位mRNA表达持续低下后逐渐增加,DG区则暂时性下降后很快回升;而免疫反应早期却未见明显改变,随后Cal和CA3区表达处于低水平,DG区和颞叶皮质表达下降后很快恢复.结论:致(癎)后2种GABAB受体亚单位基因和蛋白表达上调为颞叶EP的内源性自我保护机制.     

自发性癫痫大鼠脑内神经肽Y受体Y2R和Y5R的表达及分布

目的研究自发性癫痫大鼠(tremor rat,TRM)海马和颞叶皮质中神经肽Y(neuropeptide Y,NPY)Y2和Y5受体(Y2R和Y5R)的表达和分布。方法以TRM大鼠作为癫痫组,正常Wistar大鼠作为对照组,每组7只,以RT-PCR法检测Y2R和Y5R mRNA水平表达,Western Blot法检测其蛋白水平表达,免疫荧光法分析癫痫组和对照组大鼠海马CA1、CA3和齿状回(DG)区以及颞叶皮质中Y2R与Y5R的分布和定位。结果RT-PCR和Western Blot结果显示,与对照组大鼠相比较,癫痫组海马和颞叶皮质中Y2R mRNA相对表达水平(相对灰度值为海马:0.75±0.06 vs.0.51±0.07;颞叶皮质:0.70±0.05 vs.0.55±0.03)及蛋白相对表达水平(相对灰度值为海马:0.79±0.08 vs.0.42±0.05;颞叶皮质:0.72±0.05 vs.0.51±0.07)均显著上调(均P0.01),Y5R mRNA(相对灰度值为海马:0.52±0.10 vs.0.54±0.06;颞叶皮质:0.46±0.03 vs.0.42±0.04)及蛋白(相对灰度值为海马:0.28±0.06 vs.0.27±0.03;颞叶皮质:0.31±0.05 vs.0.27±0.07)表达均没有明显变化(均P0.05)。免疫荧光分析发现Y2R与Y5R在癫痫组大鼠海马CA1、CA3区神经元和DG区颗粒细胞以及颞叶皮质神经元中分布广泛且主要定位在细胞膜上。结论在TRM中Y2R表达在海马和颞叶皮质中均表达上调,但是Y5R的表达没有明显改变。     

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。     

自发性癫癎大鼠脑内电压门控钠通道亚型Mrna的研究

目的对照研究自发性癫癎大鼠(SER)和正常Wistar大鼠(WTC)脑内Ⅰ、Ⅱ、Ⅲ型钠通道α亚基mRNA表达情况。方法提取枕叶皮质、齿状回及海马CA1和CA3区组织总RNA,应用逆转录-聚合酶链反应(RT-PCR)及建立限制性内切酶图谱检测Ⅰ、ⅡA、ⅡN、ⅢA和ⅢN型钠通道的表达。结果SER枕叶皮质、齿状回及海马CA1和CA3区总钠通道(3.179±1.967、3.009±2.364、3.071±2.036、1.440±0.761)的表达略高于WTC(2.112±1.454、1.474±1.257、2.198±0.978、1.399±0.853),但差异均无统计学意义(P>0.05),SERⅢ型钠通道在海马的表达(1.066±0.276)高于WTC(0.419±0.098),且P<0.01,酶切图谱显示ⅢN型钠通道表达水平有明显上调。结论SER脑内海马Ⅲ型电压门控钠通道N亚型表达上调。     

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。     

GAD67/GAD65在颞叶癫痫大鼠海马内源性促痫机制中的作用

目的探讨GAD67/GAD65在颞叶癫痫发生后大鼠海马内源性促痫机制中的作用.方法112只雄性SD大鼠随机分为实验组(n=70)与对照组(n=42),实验组大鼠选用海人酸腹腔注射法建立颞叶癫痫模型,对照组大鼠腹腔注射无菌生理盐水.选取腹腔注射后3 h、6 h、12 h、24 h、48 h、7 d、30 d为研究的时间点,颞叶海马的CA1区、CA3区、齿状回为研究部位.腹腔给药后每天观察大鼠的行为学变化,大鼠处死前进行EEG描记.免疫组织化学法检测GAD65、GAD67蛋白的表达.结果海人酸致痫后6 h,实验组大鼠海马CA1区、CA3区GAD67/GAD65的比率较对照组升高(P＜0.01);海人酸致痫后30 d,实验组大鼠海马齿状回GAD67/GAD65的比率较对照组降低(P＜0.05).结论颞叶癫痫急性期CA1区、CA3区GAD67/GAD65比率的增高及慢性期齿状回GAD67/GAD65比率的降低与颞叶癫痫发生及癫痫发生后机体的内源性抗痫机制密切相关.     

颞叶癫痫大鼠海马区NR2B／PSD-95的动态表达变化

目的:观察N-甲基-D-天冬氨酸受体2亚基B(NR2B)和突触后致密物95(PSD-95)蛋白在锂-匹罗卡品致大鼠海马表达的动态变化,探讨其在颞叶癫癎发生、发展中的作用。方法:采用锂-匹罗卡品颞叶癫癎大鼠模型,用免疫组织化学法观察不同时间点大鼠海马CA1、CA3、DG区NR2B和PSD-95蛋白表达。结果:NR2B和PSD-95蛋白在大鼠海马分布广泛,表达丰富;大鼠腹腔注射锂-匹罗卡品后,NR2B和PSD-95蛋白在海马各区表达逐渐减少,24h降至低谷,与对照组比较差异有显著意义(P<0.01);此后逐渐回升,但仍低于对照组;30d在海马CA1、CA3区表达再次降低,与对照组比较有显著意义(P<0.05)。结论:NR2B和PSD-95蛋白表达下调可能分别参与颞叶癫癎急性期和慢性自发发作期的保护性机制。     

颞叶癫大鼠海马区NCX3 mRNA和蛋白的表达变化

目的:动态观察钠-钙交换体(NCX)mRNA和蛋白在氯化锂-匹罗卡品致模型大鼠海马CA1、CA3及齿状回区表达的变化,探讨其在癫发生发展中的作用。方法:用氯化锂-匹罗卡品制备癫动物模型;应用原位杂交和免疫组化技术检测各时间点NCX3mRNA和蛋白的表达。结果:急性期(6～24h)海马各区NCX3mRNA表达均随时间的延长逐渐减少;进入静止期各区表达趋向回升,慢性反复自发发作期(30、60d)各区表达又出现不同程度的两次下调。除致后6h大鼠海马各区的NCX3蛋白表达无明显变化外,NCX3蛋白变化趋势与NCX3mRNA基本一致。结论:NCX3表达下调可能通过增加神经元钙超载,改变海马神经元的兴奋性,促使癫发生。     

Metabotropic glutamate receptor 2/3 in the hippocampus of patients with mesial temporal lobe epilepsy, and of rats and mice after pilocarpine-induced status epilepticus

A comparative study of the expression of metabotropic glutamate receptor 2/3 (mGluR2/3) was done in the hippocampus of rats and mice after pilocarpine-induced status epilepticus (APISE), and of patients with mesial temporal lobe epilepsy. At 1 day APISE, there was a marked increase in mGluR2/3 immunoreactivity in the stratum lacunosum moleculare (SLM) of CA1 area and in the middle one-third of the molecular layer (MM) of the dentate gyrus. Immuno-electron microscopic study showed degenerating mGluR2/3 positive axons in the SLM of CA1 area at 1 day APISE. From 7 days, mGluR2/3 immunopositive product decreased, and by 31 days APISE, it almost disappeared in two-thirds of the SLM near CA2. In the mouse model at 2 months APISE, mGluR2/3 immunopositive product in two-thirds of the SLM near the stratum radiatum disappeared, and so did in the whole SLM of CA1 area in patients with mesial temporal lobe epilepsy. Neuropharmacological study by intravenous injection of mGluR2/3 agonist 2R,4R-4-aminopyrrolidine-2,4-dicarboxylate [(2R,4R)-APDC] at different doses at 1h during pilocarpine induced status epilepticus showed that (2R,4R)-APDC could not stop seizures and neuronal death in the hilus of the dentate gyrus. The present study, therefore, suggests that the reduction of mGluR2/3 immunopositive product in the SLM of CA1 is a consequence of neuronal loss in either the entorhinal cortex or CA1 area of the hippocampus, and at the dosage range from 12.5 to 600 mg/kg, (2R,4R)-APDC may not be effective in the prevention of seizures or neuronal death in the hilus of the dentate gyrus.     

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.     

癫痫持续状态大鼠模型的GABA_A受体亚单位α1的mRNA表达及[~3H]Flunitrazepam受体配体结合的变化

目的 :本实验研究大鼠癫痫持续状态动物模型的海马等部位 GABAA受体α1亚单位基因表达和受体一配体结合的变化。方法 :成年雄性大鼠经腹腔内注射 32 0～ 34 0± 5 .87毫克 /公斤毛果芸香碱 (Pilocarpine)以制成癫痫持续状态动物模型 ,能在癫痫持续状态 (定义为在皮质脑电图上显示痫性放电的至少 40分钟的持续性痫性发作 )下存活的大鼠在 1小时和 2小时后处于死 ,分别研究 GABA受体基因表达和放射结合位点 ,用原位杂交方法来测定脑部 m RNA水平 ,用 [3H]flunirazepam标记 GABAA 受体 benzodiazepam结合位点。结果 :动物痫性发作 2小时后海马的 CA1和CA3区域 GABAA受体 α1亚单位 m RNA显著下降 ,但是齿状回的 α1m RNA没有变化。 [3H]flunirazepam标记受体 -配体放射结合在持续 2小时持续痫性发作后可见海马的 CA1及 CA3和齿状回中均见下降 ,1小时的持续痫性发作尚未引起海马区域的任何α1m RNA或 [3H]flunirazepam受体 -配体放射结合的任何改变 ,并用结晶染色 1及 2小时后的大脑海马部位。结论 :本研究结果提示大鼠的癫痫持续状态可诱发海马区 GABAA 受体 α1基因表达的改变和 [3H]flinirazepam受体 -配体结合的下降 ,上述改变可能使大脑更容易形成慢性癫痫病灶     

Correlation of hippocampal glucose oxidation capacity and interictal FDG-PET in temporal lobe epilepsy

PURPOSE: Interictal [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) demonstrates temporal hypometabolism in the epileptogenic zone of 60-90% of patients with temporal lobe epilepsy. The pathophysiology of this finding is still unknown. Several studies failed to show a correlation between hippocampal FDG-PET hypometabolism and neuronal cell loss. Because FDG is metabolized by hexokinase bound to the outer mitochondrial membrane, we correlated the glucose-oxidation capacity of hippocampal subfields obtained after surgical resection with the corresponding hippocampal presurgical FDG-PET activity. METHODS: In 16 patients with electrophysiologically confirmed temporal lobe epilepsy, we used high-resolution respirometry to determine the basal and maximal glucose-oxidation rates in 400-microm-thick hippocampal subfields obtained after dissection of human hippocampal slices into the CA1 and CA3 pyramidal subfields and the dentate gyrus. RESULTS: We observed a correlation of the FDG-PET activity with the maximal glucose-oxidation rate of the CA3 pyramidal subfields (rp = 0.7, p = 0.003) but not for the regions CA1 and dentate gyrus. In accordance with previous studies, no correlation of the FDG-PET to the neuronal cell density of CA1, CA3, and dentate gyrus was found. CONCLUSIONS: The interictal hippocampal FDG-PET hypometabolism in patients with temporal lobe epilepsy is correlated to the glucose-oxidation capacity of the CA3 hippocampal subfield as result of impaired oxidative metabolism.     

Do Interictal Discharges Promote or Control Seizures? Experimental Evidence from an In Vitro Model of Epileptiform Discharge

Summary: Interictal and ictal discharges are recorded from limbic structures in temporal lobe epilepsy patients. In clinical practice, interictal spikes are used to localize the epileptogenic area, but they also are assumed to promote ictal events. Here I review data obtained from combined slices of mouse hippocampus–entorhinal cortex that indicate an inverse relation between interictal and ictal events. In this preparation, application of 4-aminopyridine or Mg²⁺-free medium induce (a) interictal discharges that originated from CA3 and propagate (via the Schaffer collaterals) to CA1 and entorhinal cortex, to return to the hippocampus through the dentate area; and (b) ictal discharges that initiate in the entorhinal cortex and propagate to the hippocampus via the dentate gyrus. Interictal activity occurs throughout the experiment (up to 6 h), whereas ictal discharges disappear after 1–2 h. Schaffer collateral cut abolishes interictal discharges in CA1, entorhinal cortex, and dentate and reestablishes entorhinal ictal discharges. Moreover, ictal discharge generation in the entorhinal cortex after Schaffer collateral cut is prevented by mimicking CA3 activity with rhythmic electrical stimulation of CA1 outputs. Thus hippocampal interictal activity controls the ability of the entorhinal cortex to generate seizures. It also may be proposed that Schaffer collateral cut may model the epileptic condition in which CA3 damage results in loss of hippocampal control over the entorhinal cortex. In conclusion, these experiments demonstrate that interictal activity controls rather than promotes ictal events, and functional integrity of CA3 constitutes a critical control mechanism in temporal lobe epilepsy.     

Differential expression of phospholipase D isozymes in the hippocampus following kainic acid-induced seizures

To investigate the pathophysiological role of phospholipase D (PLD)-mediated signaling, changes in the expression of the PLD isozymes PLD1 and PLD2 were investigated in the rat kainic acid (KA) model of human temporal lobe epilepsy. Western blot analysis showed a significant increase in the expression of PLD1 and PLD2 in the postictal hippocampus. PLD1 immunoreactivity increased preferentially in the CA3 and CA1 regions, where pyramidal neurons are susceptible to temporal lobe epilepsy. Experiments employing double immunofluorescence revealed that the cells expressing PLD1 were GFAP-expressing reactive astrocytes. By contrast, PLD2 immunoreactivity increased strikingly in infrapyramidal, but not in suprapyramidal granule cells of the postictal dentate gyrus, fitting well with results of the PLD activity assay. Considering that PLD belongs to a key signaling pathway, this result suggests that changes in granule cell activity in the dentate gyrus after seizures occurs specifically between the supra- and infrapyramidal blades. In addition, enhanced immunoreactivity of PLD2 was observed in the reactive astrocytes of the CA1, CA3, and hilar subregions, but its temporal pattern is different from that of PLD1. Taken together, our results suggest that PLD1 and PLD2 exercise their unique pathophysiological functions in the rat hippocampus after KA-induced seizures.