海马干细胞移植对癫痫鼠苔状纤维发芽抑制作用的研究

Turner等证实大鼠海马胚胎细胞移植对于海人酸（KA）所致癫痫鼠神经元的损害具有一定的修复作用，但胚胎细胞移植受细胞来源和伦理学等多方面限制。神经干细胞的发现为细胞移植治疗颞叶癫痫等神经系统疾病提供了广阔前景。本研究将分离培养的大鼠海马干细胞移植至KA所致癫痫模型鼠CA3区，     

颞叶癫痫患者海马硬化神经元脱失的亚群特点

目的探讨颞叶癫痫患者海马硬化神经元脱失的亚群特点。方法颞叶癫痫患者中8例海马硬化和7例非海马硬化，以正常海马解剖为对照，观察两患者组海马各亚群神经元脱失情况。结果海马硬化组和非海马硬化组均有CA1、CA3锥体细胞和颗粒细胞脱失，海马硬化组明显。门区神经元脱失仅在海马硬化组可见。结论颞叶癫痫患者海马结构主要细胞脱失，门区神经元脱失是海马硬化的主要特点。海马硬化的形成与齿状回尤其是门区神经元的关系更为密切。     

大鼠背根神经节细胞的纯化培养

目的:在NB1培养基中建立体外胚胎大鼠背根神经节(DRG)细胞的纯化培养体系。方法:取胎鼠的背根神经节,用胰蛋白酶消化法分离成单细胞,通过差速贴壁法进行背根神经节神经元的分离纯化,在NB1中培养,用活细胞计数和神经元特异性的烯醇化酶(NSE)免疫组织化学染色相结合判定培养神经元的纯度。结果:纯化培养神经元生长状态良好,培养4天时神经元纯度为91％左右。结论:采用差速贴壁法可获得高纯度的神经元,可作为神经科学研究的重要工具。     

实验性癫痫大鼠颞叶及海马损害的病理学观察

目的　观察癫痫持续不同时间脑组织学损害特点。方法　Wistar大鼠 80只 ,以 1 0 %Pilocarpine 350mg/kg腹腔注射 ,诱发强直 痉挛全面大发作持续状态 ,脑标本制成 30 μm层厚的横轴位切片 ,HE染色 ,光镜下观察癫痫持续 5min至 60h颞叶、海马组织学改变 ,并对海马CA1 区和CA3 区神经元丢失做了定量计数。结果　癫痫持续 (SE) 5～ 30min,颞叶、海马区以神经元变性为主 ;SE 30min～ 3h,轻度神经元坏死、丢失及胶质增生 ;癫痫持续 3h～ 6h后 ,可见颞叶、海马区严重神经元脱失、胶质增生 (即近中颞叶硬化 ,MTS)和脑水肿 ;CA1 区和CA3 区神经元丢失与发作持续时间相关。结论　①随着癫痫持续时间延长 ,神经元损伤加重。②大鼠癫痫持续 3h以上 ,可形成MTS。③大鼠对pilocarpine诱导的持续性癫痫的神经元损伤的易感区依次为CA1 >CA3>齿状回 >CA2 >颞叶     

颞叶内侧硬化的组织学分型及临床病理相关性

目的 探讨颞叶内侧硬化组织学特点和分型以及临床病理的相关性.方法 对51例颞叶内侧癫痫患者的手术切除标本,行神经元核抗原(NeuN)免疫组织化学染色后显微镜下计数海马4个亚区神经元数量,进行统计学分析(k-均值聚类分析).同时收集患者的临床资料,包括初次发作癫痫的年龄、有无突发脑损伤、潜伏期、癫痫病程、术后半年及1年癫痫疗效Engel评分,分析不同病理类型的临床特点.另选取8例无神经系统病变的尸检患者的海马标本作为对照组.结果 (1)海马神经元丢失表现为5种不同的组织学类型:1a型(21/51,41.18％):CA1区神经元重度丢失同时伴有CA3、CA4区神经元轻度丢失,CA2区神经元无明确丢失;1b型(18/51,35.29％):所有亚区神经元均严重丢失;2型(9/51,17.65％):仅有CAt区神经元重度丢失;3型(1/51,1.96％):仅CA4区神经元重度丢失;无海马硬化型(2/51,3.92％):与对照组相比海马各亚区神经元无明显丢失.(2)1型(1a、1b)海马硬化患者首次发作癫痫的年龄更小,潜伏期及病程更长,有突发脑损伤病史的比例更高,其中有热性惊厥病史的1 a型:10/19,1b型:7/16,2型:4/7,3型:0(x2=11.790,P =0.019).(3)海马硬化严重程度与手术预后呈正相关.结论 1型海马硬化为颞叶内侧硬化中最常见的类型,与早期突发脑损伤尤其是热性惊厥密切相关,术后癫痫的控制率高于其他三型.     

神经干细胞和GABA能神经元治疗大鼠颞叶癫痫实验研究

目的探讨并比较神经干细胞(NSCs)和γ-氨基丁酸(GABA)能神经元移植治疗大鼠颞叶癫痫的疗效。方法取孕12 d SD大鼠胎鼠脑组织,分离培养NSCs并鉴定,取第3代NSCs定向诱导分化为GABA能神经元。48只SD大鼠随机分为4组,空白对照组、未移植组、NSCs移植组和GABA能神经元移植组,移植细胞用5-溴脱氧尿苷(BrdU)标记,在模型建立后的第4 d将上述两种细胞移植到癫痫大鼠右侧海马。分别在细胞移植后的4 w、8 w、12 w处死大鼠留取脑标本。常规HE染色和Nissl染色观察大鼠右侧海马的损伤与治疗情况并进行评价。结果 NSCs移植组和GABA能神经元移植组均于移植后第8 w时海马CA3(CA3)区神经元计数最多,组内比较时,与另外两个时间点之间的差异具有统计学意义(P<0.05)。进而取第8 w时间点进行组间比较,结果各组海马区神经元计数之间的差异均具有统计学意义(P<0.05)。结论两治疗组在移植后第8 w时海马区神经元计数最多,且NSC移植组的疗效优于GABA能神经元移植组。     

神经干细胞向γ-氨基丁酸能神经元的诱导分化

目的探索海马神经干细胞在特定条件下分化成γ-氨基丁酸能神经元的情况,为颞叶癫痫的细胞替代学治疗奠定基础。方法新生大鼠海马组织中的神经干细胞在体外增殖后,加入特定的细胞因子进行诱导,使其向γ-氨基丁酸能神经元分化,对分化的细胞进行神经元烯醇化酶（NSE）、微管相关蛋白（MAP-2）、γ-氨基丁酸（GABA）、胶质纤维酸性蛋白（GFAP）和半乳糖脑苷脂酶（GalC）免疫荧光染色鉴定,判断其分化成γ-氨基丁酸能神经元的情况。结果海马神经干细胞诱导贴壁后即发生分化,其中几乎全部分化成神经元（γ-氨基丁酸能神经元）,只有极少的胶质细胞和少突胶质细胞形成。结论从海马神经干细胞中几乎可以完全诱导形成γ-氨基丁酸能神经元,这为颞叶癫痫的细胞替代学治疗奠定了基础。     

糖皮质激素对大鼠海马神经元影响的体外研究

目的　探讨在体外条件下糖皮质激素 (glucocorticoids ,GCs)对海马神经元的影响及其机制。方法　取新生大鼠海马组织进行原代分离培养 ,通过细胞形态学观察、细胞酶学噻唑蓝 (methylthiazolyl,MTT)测定、DNA原位末端标记 (TdT mediateddUTPNickEndLablelingmethod ,TUNEL)法以及凋亡相关蛋白Bcl 2、Bax的表达观察 0、10 - 9、10 - 8、10 - 7、10 - 6 、10 - 5mol/L不同浓度的地塞米松 (dexam ethasone ,DEX)作用 2 4h对大鼠海马神经元的影响。结果　高浓度的DEX可以引起明显的海马神经元形态变化 ,降低海马神经元的活性 ,并通过上调Bax的表达 ,下调Bcl 2的表达促进海马神经元的凋亡。结论　高浓度糖皮质激素可促进海马神经元的凋亡从而降低海马神经元的活性。     

普瑞巴林对慢性颞叶癫癎大鼠海马凋亡调控基因的影响

目的通过观察普瑞巴林对匹罗卡品慢性癫癎大鼠海马区Bcl-2和Bax表达的影响,探讨普瑞巴林治疗癫癎的药理学机制及对大鼠海马神经元的抗凋亡作用。方法采用氯化锂-匹罗卡品化学诱导方法建立慢性颞叶癫癎模型。经腹腔注射普瑞巴林40mg(/kg·d)连续治疗3周,免疫组织化学染色和Western blotting法检测不同处理组大鼠海马区Bcl-2和Bax表达变化。结果与生理盐水对照组比较,模型组大鼠海马区Bcl-2和Bax表达水平显著升高(均P=0.000);与模型组比较,普瑞巴林治疗组大鼠海马区Bcl-2表达水平升高、Bax表达水平降低,组间差异具有统计学意义(均P=0.000)。结论新型抗癫癎药物普瑞巴林可通过降低慢性颞叶癫癎大鼠海马区Bax表达、上调Bcl-2表达而抑制细胞凋亡,发挥神经元保护作用。     

海马硬化型癫痫颞叶的病理学及c-fos、c-jun表达研究

目的研究海马硬化型颞叶癫痫（TLE）患者颞叶皮层神经元的变性凋亡以及c—fos、c-jun表达，并与海马的相应变化进行比较。方法14例颞叶和海马标本制成脑片后，用尼氏染色和TUNEL染色观察神经细胞变性和凋亡，并计数神经细胞数量；同时，研究c—fos和c-jun表达以反映癫痫发作对神经元损伤的程度和范围。结果颞叶皮层的神经细胞数量明显减少且形态异常，并有较多的凋亡细胞，伴有胶质细胞增生，而且有c—fos和c-jun的大量表达；其表现与海马的相应变化相似，但颞叶的胶质细胞增生更为明显。与对照组比较差异有统计学意义（P〈0．01或P〈0．05）。结论除海马外，颞叶神经细胞和胶质细胞的病理改变可能参与海马硬化型TLE的发生和传播过程。     

Alterations of hippocampal acetylcholinesterase in human temporal lobe epilepsy

Hippocampal sclerosis is the most common pathological finding associated with human temporal lobe epilepsy. Histochemical study with acetylcholinesterase (AChE) staining was used to investigate 7 surgically resected temporal lobes with hippocampal sclerosis from patients with temporal lobe epilepsy. In all 7 specimens, an abnormal but consistent pattern of staining was noted. In the hilum of the dentate gyrus, AChE-rich polymorphic cells were relatively preserved in comparison to the pyramidal neurons. In Ammon's horn, AChE fibers were lost in regions corresponding to the pyramidal cell dropout. AChE fibers were also lost along the inner portion of the molecular layer of the dentate gyrus, yet they were preserved within the outer portions of the molecular layer. These findings provide additional evidence for the relative selectivity of hippocampal pathology in human temporal lobe epilepsy.     

Septo-hippocampal networks in chronic epilepsy

The medial septum inhibits the appearance of interictal spikes and seizures through theta rhythm generation. We have determined that medial septal neurons increase their firing rates during chronic epilepsy and that the GABAergic neurons from both medial and lateral septal regions are highly and selectively vulnerable to the epilepsy process. Since the lateral septal region receives a strong projection from the hippocampus and its neurons are vulnerable to epilepsy, their functional properties are probably altered by this disorder. Using the pilocarpine model of temporal lobe epilepsy we examined the pilocarpine-induced functional alterations of lateral septal neurons and provided additional observations on the pilocarpine-induced functional alterations of medial septal neurons. Simultaneous extracellular recordings of septal neurons and hippocampal field potentials were obtained from chronic epileptic rats under urethane anesthesia. Our results show that: (1) the firing rates of lateral septal neurons were chronically decreased by epilepsy, (2) a subset of lateral septal neurons increased their firing rates before and during hippocampal interictal spikes, (3) the discharges of those lateral septal neurons were well correlated to the hippocampal interictal spikes, (4) in contrast, the discharges of medial septal neurons were not correlated with the hippocampal interictal spikes. We conclude that epilepsy creates dysfunctional and uncoupled septo-hippocampal networks. The elucidation of the roles of altered septo-hippocampal neuronal populations and networks during temporal lobe epilepsy will help design new and effective interventions dedicated to reduce or suppress epileptic activity.     

A selective loss of somatostatin in the hippocampus of patients with temporal lobe epilepsy.

Although neuropeptides have been demonstrated to be hippocampal neuromodulators in laboratory animals, their role in human hippocampal physiology or pathophysiology remains to be defined. The concentrations of somatostatin, cholecystokinin octapeptide, vasoactive intestinal polypeptide, and dynorphin A 1-17 were determined in hippocampal tissue resected from patients with cryptogenic temporal lobe epilepsy, a common seizure disorder originating in or near the hippocampus. Control tissue was obtained from cadavera or epilepsy patients in whom the hippocampus was removed during the resection of temporal lobe tumors. Peptide determinations were performed on extracts of punch biopsy specimens taken from six different hippocampal regions. A significant decrease in immunoreactive somatostatin concentration was identified in the dentate gyrus and in region cornu ammonis 4 of cryptogenic temporal lobe epilepsy specimens. No significant changes were present in any other hippocampal region or in the levels of other peptides. In situ hybridization studies performed on cryostat sections from similar patients confirmed a marked loss of neurons expressing the somatostatin gene, which was restricted to the dentate hilus. The density of specific 125I-somatostatin binding to cryostat sections, as determined by semiquantitative in vitro autoradiography, was significantly increased in the dentate gyrus of the cryptogenic epilepsy patients, compared with tumor control specimens. We conclude that a loss of somatostatin-producing interneurons with an upregulation of dentate somatostatin receptors is a specific and characteristic element in the pathophysiology of human cryptogenic temporal lobe epilepsy.     

Preservation of mitochondrial integrity and energy metabolism during experimental status epilepticus leads to neuronal apoptotic cell death in the hippocampus of the rat

Status epilepticus results in mitochondrial damage or dysfunction and preferential neuronal cell loss in the hippocampus. Since a critical determinant of the eventual cell death fate resides in intracellular ATP concentration, we investigated whether mitochondrial integrity and level of energy metabolism are related with apoptotic cell death in specific hippocampal neuronal populations. A kainic acid (KA)-induced experimental temporal lobe status epilepticus model was used. Qualitative and quantitative analysis of DNA fragmentation, TUNEL immunohistochemistry, double immunofluorescence staining for activated caspase-3, electron microscopy or measurement of ATP level in the bilateral hippocampus was carried out 1, 3 or 7 days after microinjection unilaterally of a low dose of KA (0.5 nmol) into the CA3 hippocampal subfield. Characteristic biochemical (DNA fragmentation), histochemical (TUNEL or activated caspase-3 staining) or ultrastructural (electron microscopy) features of apoptotic cell death were presented bilaterally in the hippocampus 7 days after the elicitation of sustained hippocampal seizure activity by microinjection of KA into the unilateral CA3 subfield. At the same time, CA3 or CA1 subfield on either side manifested a maintained ATP level; alongside relatively intact mitochondria, rough endoplasmic reticulum, Golgi apparatus or cytoplasmic membrane in hippocampal neurons that exhibited ultrastructural features of apoptotic cell death. Our results demonstrated that preserved mitochondrial ultrastructural integrity and maintained energy metabolism during experimental temporal lobe status epilepticus is associated specifically with apoptotic, not necrotic, cell death in hippocampal CA3 or CA1 neurons.     

颞叶内侧癫(癎)海马CA1区CytC、caspase-9、caspase-3蛋白的表达研究

目的 探讨凋亡相关蛋白细胞色素C(CytC)、caspase-9、caspase-3在颞叶内侧癫(癎)(MTLE)病人致(癎)海马CA1区神经元内的表达及意义.方法 选择30例典型MTLE病人为实验组,6例颢叶深部血管畸形病人为对照组.采用苏木精-伊红染色、原位末端标记(TUNEL)方法在光镜下观察MTLE病人致(癎)海马CA1区神经元凋亡的情况.采用免疫组化S-P法检测并比较MTLE海马CA1区与对照组海马组织神经元内凋亡相关蛋白CytC、caspase-9、caspase-3的表达.结合病史资料,分析caspase-3表达水平与癫(癎)病程和发作频率的相关性.结果 MTLE组致(癎)海马CA1区光镜下可观察到神经元退变、噬神经元现象,TUNEL染色发现凋亡神经元18例,对照组则为阴性;CytC、caspase-9、caspase-3蛋白在MTLE组海马CA1区均有明显表达,对照组中则呈轻微表达,差异显著(P<0.01).caspase-3蛋白表达水平与发作频率呈正相关,而与病程长短无关.结论 MTLE致(癎)海马神经元中存在外源性凋亡途径,这可能是癫(癎)发展的重要因素之一.     

锂-匹罗卡品诱导癫痫持续状态大鼠海马CA1，CA3和PG区P糖蛋白的动态表达

【背景】药物抗性癫痫的病理生理机制目前还不清楚。现有的证据提示P糖蛋白可能参与了药物抗性癫痫的形成。【目的】观察锂-匹罗卡品诱导的大鼠慢性颞叶内侧癫痫模型中海马不同分区P糖蛋白是否出现过度表达,并进而探讨其表达与癫痫发作频度是否相关。【方法】选择6-8周雌性SD大鼠,予锂-匹罗卡品诱导大鼠形成颞叶内侧癫痫慢性模型,对大鼠进行行为学观察及视频脑电记录;Western-Blot、实时定量RT-PCR及免疫组化方法分别检测P糖蛋白在处理组、假处理组、空白对照组中不同时间点（1d及60d）海马不同分区（CA1、CA3及DG）的表达情况。【结果】87.5％（35/40）的大鼠在锂-匹罗卡品诱导的急性期出现惊厥持续状态,伴有与临床癫痫全身发作类似的脑电变化;慢性期出现自主发作,发作间期脑电记录可见到痫性放电;与对照组相比,模型鼠急性期及慢性期在海马CA1、CA3及DG区均出现P糖蛋白的过度表达,增加约70％以上(p<0.05);应用免疫组化染色发现P糖蛋白阳性显色定位于锥体细胞层神经元上。【结论】在慢性颞叶内侧癫痫模型中急性期及慢性期海马锥体细胞层神经元均出现P糖蛋白的过度表达,并证实P糖蛋白的过度表达可能与痫性发作密切相关,但非发现其表达程度与发作频度相关。     

Neuronal and glial metabolite content of the epileptogenic human hippocampus

Mesial temporal lobe epilepsy is characterized by hippocampal atrophy, hypometabolism, and decreased N-acetylaspartate, often attributed to neuron loss and gliosis. Twenty hippocampal specimens were obtained during temporal lobectomy and frozen quickly. Perchloric acid extracts of the small metabolites were analyzed by proton magnetic resonance spectroscopy. There were no significant associations between hippocampal neuron loss and the cellular content of N-acetylaspartate, glutamate, GABA, glutamine, or aspartate. The mean metabolite content of hippocampi with less than 30% of neurons remaining was the same as those with greater than 65% of neurons surviving. Mean N-acetylaspartate levels were below those reported by in vivo studies of control subjects. The highest and the lowest glutamate concentrations were seen in specimens with the worst neuron loss. A highly significant association between hippocampal N-acetylaspartate and glutamate content was seen with weak associations between N-acetylaspartate and aspartate and glutamate and aspartate. The hippocampal content of N-acetylaspartate, glutamate, GABA, glutamine, and aspartate is altered minimally by severe neuron loss in mesial temporal lobe epilepsy. The epileptic human hippocampus has increased intracellular glutamate content that may contribute to the epileptogenic nature of hippocampal sclerosis.     

Physiologic properties of human dentate granule cells in slices prepared from epileptic patients.

The neurophysiological properties of human dentate granule cells were studied in hippocampal slices prepared from patients undergoing surgical treatment for medically intractable temporal lobe epilepsy. In 24 neurons which were morphologically identified as dentate granule cells by intracellular staining with biocytin, there were 2 types of synaptic responses to perforant path stimulation: one showed an EPSP-IPSP sequence (n = 10) and the other showed prolonged EPSPs without accompanying hyperpolarizing IPSPs (n = 14). The prolonged EPSPs were markedly retarded by the application of an NMDA receptor antagonist, APV. Membrane properties of neurons showing the different classes of synaptic responses were similar in resting membrane potential (pooled average: -56.2 mV +/- 0.94 SEM) and spike amplitude (pooled average: 65.2 mV +/- 1.69 SEM). However, membrane resistance tended to be lower in neurons with prolonged EPSPs (31.8 M omega +/- 2.63 SEM) than in neurons that showed EPSP-IPSP responses (40.2 +/- 4.33) (P less than 0.05, Fisher). No spontaneous and/or evoked burst firing was observed. These data provide fuller information on the neurophysiological properties of human dentate granule cells in surgically resected epileptogenic hippocampus, implicating a role of NMDA receptor activation in human temporal lobe epilepsy.     

Targeted hippocampal GABA neuron ablation by Stable Substance P–saporin causes hippocampal sclerosis and chronic epilepsy in rats

Cryptogenic temporal lobe epilepsy develops in the absence of identified brain injuries, infections, or structural malformations, and in these cases, an unidentified pre‐existing abnormality may initiate febrile seizures, hippocampal sclerosis, and epilepsy. Although a role for GABAergic dysfunction in epilepsy is intuitively obvious, no causal relationship has been established. In this study, hippocampal GABA neurons were targeted for selective elimination to determine whether a focal hippocampal GABAergic defect in an otherwise normal brain can initiate cryptogenic temporal lobe epilepsy with hippocampal sclerosis. We used Stable Substance P–saporin conjugate (SSP‐saporin) to target rat hippocampal GABA neurons, which selectively and constitutively express the neurokinin‐1 receptors that internalize this neurotoxin. Bilateral and longitudinally extensive intrahippocampal microinjections of SSP‐saporin caused no obvious behavioral effects for several days. However, starting ~4 days postinjection, rats exhibited episodes of immobilization, abnormal flurries of “wet‐dog” shakes, and brief focal motor seizures characterized by facial automatisms and forepaw clonus. These clinically subtle behaviors stopped after ~4 days. Convulsive status epilepticus did not develop, and no deaths occurred. Months later, chronically implanted rats exhibited spontaneous focal motor seizures and extreme hippocampal sclerosis. These data suggest that hippocampal GABAergic dysfunction is epileptogenic and can produce the defining features of cryptogenic temporal lobe epilepsy.