血管性痴呆大鼠海马区核因子-κB、环氧合酶-2的表达变化

目的通过检测血管性痴呆(vascular dementia,VD)大鼠海马CA1区核因子-κBp65(nuclear factor-κB p65,NF-κBp65)与环氧合酶-2(cyclooxygenase-2,COX-2)的表达,探讨NF-κB、COX-2对VD大鼠的损伤作用。方法28只大鼠随机分为两组,假手术(SOG)组(n=13)和模型(VD)组(n=15),采用HE染色,光镜下观察海马CA1区锥体细胞的改变,免疫组化方法检测海马CA1区NF-κBp65、COX-2蛋白的表达。结果与假手术组相比,模型组组海马CA1区锥体细胞损伤、丧失明显,NF-κBp65、COX-2蛋白表达高于假手术组,与假手术组相比有统计学意义(P(0.01)。结论血管性痴呆大鼠海马CA1区NF-κBp65、COX-2蛋白的表达增加,NF-κBp65、COX-2蛋白的高表达可能是学习记忆障碍的原因之一。     

小檗碱对癫痫大鼠脑组织P-糖蛋白表达的影响

目的 探讨小檗碱(BBR)对癫痫大鼠脑组织P-糖蛋白(P-gp)表达的影响.方法 将44只SD大鼠随机分为假手术组(9只)、癫痫组(9只)和BBR 10 mg/kg(9只)、20 mg/kg(9只)、40 mg/kg组(9只).采用大鼠海马注射海人酸方法制作癫痫模型,各BBR干预组分别于术前48 h、术前24h和术后6h腹腔注射相应剂量BBR.观察各组大鼠癫痫发作潜伏期及发作严重程度.造模24 h后,采用免疫组化方法检测并比较各组大鼠海马CA3区P-gp和核因子-κB(NF-κB) p65的表达水平.结果 BBR 20 mg/kg组[(66.11±5.90) min,(26.67±6.67) min]和40 mg/kg组[(76.33±9.11) min,(42.00±7.73) min]大鼠癫痫发作潜伏期及初次至第6次≥Ⅳ级痫样发作间隔时间均明显长于癫痫组[(41.78±10.45) min,(9.44±4.25)min](均P＜0.05).各组大鼠海马CA3区NF-κB p65和P-gp表达的差异均有统计学意义(H=16.024,H=21.830;均P＜0.01).癫痫组海马CA3区NF-κB p65和P-gp表达显著高于假手术组(均P＜0.05);BBR 20mg/kg和40 mg/kg组表达显著低于癫痫组(均P＜0.05).结论 BBR能够延长癫痫发作潜伏期、降低其严重程度,并抑制癫痫大鼠脑组织NF-κB和P-gp的表达.     

低频重复经颅磁刺激对颞叶癫痫大鼠海马NF-κB及COX-2表达的影响

目的 研究低频重复经颅磁刺激(rTMS)对颞叶癫痫模型大鼠海马核转录因子κB(NF-κB)和环争化酶2(COX-2)表达的影响,进而从炎症反应角度探讨rTMS治疗癫痫的可能机制.方法 30只雄性SD大鼠随机分为颞叶癫痫刺激组(TIE+rTMS)、颢叶癫痫假刺激组(TLE+s-rTMS)和生理盐水对照组(NS),每组10只.利用立体定位仪向大鼠海马CA,区微量注射海人酸(KA)制备颞叶癫痫模型,对照组于同部位注射等量生理盐水.刺激组连续接受rTMS治疗10d.采用免疫组织化学染色、蛋白质印迹法(western blotting)研究大鼠海马NF-κBp65和COX-2表达情况.结果 与生理盐水对照组大鼠比较,造模后大鼠海马组织中NF-κBp65和COX-2表达明显增强NF-κBp65核移位增多,差异均有统计学意义(P＜0.05),TLE+rTMS组大鼠海马组织中NF-κBp65和COX-2表达较TLE+s-rTMS组明显降低,NF-κBp65核移位减少,差异均有统计学意义(P＜0.05).结论 rTMS可能通过降低癫痫大鼠海马NF-κB和COX-2的表达,阻止NF-κB核移位,从而抑制炎症反应发挥抗癫痫作用.     

血管性痴呆大鼠海马区核因子-κB、环氧合酶-2的表达变化

目的 通过检测血管性痴呆(vascular dementia,VD)大鼠海马CA1区核因子-κBp65(nuclear factor-κB p65, NF-κBp65)与环氧合酶-2(cyclooxygenase-2,COX、2)的表达,探讨NF -κB和COX-2的损伤作用.方法 28只大鼠随机分为假手术组(SOG)13只和模型组(VD)15只,取海马CA1区为观察部位,HE染色观察锥体细胞的改变,免疫组化检测NF-κBp65、COX-2的表达.结果 与SOG相比,VD大鼠海马CA1区锥体细胞损伤、丧失明显,NF-κBp65、COX-2蛋白增加,差异有统计学意义(P﹤0.01).结论 VD大鼠海马CA1区NF-κBp65、COX-2蛋白的高表达可能是学习记忆障碍的原因之一.     

PDTC对慢性致痫大鼠海马NF-κB及IL-10表达的影响

目的研究NF-κB信号传导通路抑制剂吡咯烷二硫代氨基甲酸盐(PDTC)对慢性致痫大鼠海马组织中核转录因子κB(NF-κB)和白细胞介素-10(IL-10)表达的影响。方法通过腹腔注射亚惊厥量的戊四氮(PTZ)来建立慢性癫痫大鼠模型,并将大鼠分为PTZ模型组、PTZ+PDTC干预组和生理盐水对照组。实验14d、21d、28d和35d分别取大鼠海马组织检测,用实时荧光定量PCR检测癫痫大鼠海马组织中NF-κB/P65和IL-10mRNA的表达,用酶联免疫吸附试验(ELISA)检测海马组织中IL-10蛋白的表达。结果 PTZ模型组海马组织中NF-κB p65 mRNA的表达于14d开始增高,持续至28d,35d后恢复至14d水平,与对照组之间比较差异具有统计学意义(P<0.01);经PDTC干预后,NF-κB p65 mRNA的表达明显低于模型组,差异具有统计学意义(P<0.001)。海马组织中IL-10经过PDTC干预后,IL-10 mRNA的表达也明显低于模型组(P相似文献   

核因子-κB活性抑制剂对癫(癎)大鼠的脑保护作用

目的 研究核因子-κB(NF-κB)活性抑制剂吡咯烷二硫代氨基甲酸盐(PDTC)对癫(癎)大鼠的脑保护作用.方法 将36只雄性SD大鼠随机分为癫(癎)组(14只)、PDTC干预组(PDTC组,14只)和假手术组(8只).采用海马注射海人酸(KA)方法制作癫(癎)大鼠模型,PDTC组大鼠造模前30 min给于腹腔注射PDTC150 mg,/kg;观察各组大鼠癫(癎)发作的潜伏期和初次至第6次≥Ⅳ级发作的时间(发作严重程度).应用HE染色和免疫组织化学染色,观察各组大鼠海马CA3区残存神经元数和NF-κB的表达.结果 PDTC组大鼠癫(癎)发作潜伏期[(89.6±39.3)min]长于癫(癎)组[(67.5±22.9)min],但差异无统计学意义;PDTC组初次至第6次≥Ⅳ级发作的时间[(29.2±20.4)min]较癫(癎)组[(12.1±4.0)min]显著延长(P＜0.05);与癫(癎)组相比,PDTC组大鼠海马CA3区残存神经元数显著增多(P＜0.05),NF-κB表达水平显著降低(P＜0.01),二者间呈负相关(r=-0.562,P=0.001).结论 NF-κB活性抑制剂能降低癫(癎)发作严重程度,减少海马神经元的变性死亡,具有脑保护作用.提示癫(癎)发作所致脑组织损伤可能与NF-κB活化有关.     

杏仁核点燃癫痫大鼠P-糖蛋白及苔藓纤维出芽变化的研究

目的 观察杏仁核点燃癫痫大鼠海马区P-糖蛋白(P-gp)表达及苔藓纤维出芽(MFS)的动态变化. 方法 90只大鼠采用随机数字表法分为假手术对照组(10只)、癫痫组(40只)和治疗组(40只),假手术对照组只安装电极,不予刺激;癫痫组和治疗组制作杏仁核点燃模型,治疗组加用左乙拉西坦灌胃治疗[100 mg/(kg·d),2次/d)].采用Timm银染组织化学方法观察海马区MFS,免疫组化法检测P-gp的表达. 结果 (1)成功制造癫痫模型后,在海马CA3区透明层出现异常MFS,其中S1亚组大鼠MFS评分最低,与假手术对照组比较差异无统计学意义(P＞0.05);S2亚组大鼠评分开始增高,S4亚组大鼠明显增高,S8亚组大鼠达到高峰,与假手术对照组比较差异均有统计学意义(P＜0.05).而治疗组大鼠MFS评分各时间点与假手术对照组比较差异均无统计学意义(P＞0.05).(2)癫痫发作后癫痫组大鼠P-gp表达量呈现出逐渐降低的趋势,S1、S2、S4亚组与假手术对照组差异有统计学意义(P＜0.05);S8亚组接近正常水平,与假手术对照组比较差异无统计学意义(P＞0.05).治疗组大鼠除Y1亚组外,余各亚组P-gp表达量与假手术对照组比较差异均无统计学意义(P＞0.0S). 结论 MFS是慢性癫痫形成的重要机制,P-gp是癫痫发生的产物,是癫痫药物耐药的主要原因.     

Toll样受体4/核因子-κB信号通路在癫癎持续状态大鼠海马损伤中的作用

目的 通过观察癫疴持续状态(status epilepticus,SE)后大鼠海马Toll样受体4(Toll-like receptor 4,TLR4)及核因子-κB(nuclear factor KB,NF-κB)的表达;并观察应用NF-κB抑制剂吡咯烷二硫代氨基甲酸盐(PDTC)后,对TLR4/NF-κB信号通路及海马损伤的影响,探讨TLR4/NF-κB信号通路在SE后大鼠海马损伤的发生发展过程中的作用.方法 106只SD大鼠随机分为对照组(A组)、SE组(B组)和PDTC干预组(C组),其中B组再随机分为B1～B4组(分别于惊厥后4、24、48和72 h处死),B组和C组采用氯化锂.匹罗卡品法制作大鼠SE模型,C组在大鼠惊厥终止后30 min,给予100 mg/kg PDTC腹腔注射,每天1次,连用3 d.光镜下观察大鼠海马病理学改变;免疫组织化学法检测海马TLR4和NF-κB/p65蛋白的表达变化;逆转录-聚合酶链反应(RT-PCR)技术检测海马TLR4 mRNA表达的动态改变.结果 长程惊厥发作后,脑内神经元损伤存在动态变化,在72 h内随着观察时间的延长,神经元损伤逐渐加重,C组改变较B4组明显减轻.B组各时间点TLR4蛋白的表达(B1组0.1287±0.0260,B2组0.1296±0.0285,B3组0.1330 4-0.0329,B4组0.1604 4-0.0457)均明显高于A组(0.0964±0.0324,t=0.0641～0.3236,P<0.05),并随时间延长明显增高;C组TLR4蛋白表达(0.1271±0.0330)较B4组显著降低(t=-0.0334,P<0.01).B组可见NF-κB/p65蛋白在胞核内有不同程度表达,与A组比较差异有统计学意义(P<0.05);C组与B4组比较,NF-κB/p65蛋白表达水平明显降低(P<0.01).B组各时间点TLR4 mRNA的表达均较A组(0.268±0.072)高(P<0.05),且随时间延长逐步升高,惊厥后72 h达到高峰(1.242±0.100);C组海马TLR4 mRNA的表达(0.984±0.263)明显低于B4组(t=-0.2578,P<0.05).各组TLR4的表达情况与NF-κB/p65一致.结论 ,TLR4及NF-κB/p65在SE后的大鼠海马中表达升高,NF-κB抑制剂PDTC可以下调TLR4的表达,并减轻惊厥后海马病理损伤程度,提示TLR4/NF-κB信号通路在惊厥后海马损伤的发生发展过程中起促进作用.     

海马神经细胞活化在戊四氮点燃大鼠癫痫形成过程中的作用

目的 以核因子κB/P65(nuclear factor κB,NF-κB/P65)的核转位作为神经细胞活化的标志,观察在戊四氮(pentylenetetrazol,PTZ)点燃大鼠出现惊厥之前,即点燃过程中海马神经细胞NF-κB活化在癫痫形成过程中的作用.方法 将大鼠随机分为对照组、非药物干预组、药物干预组(苯巴比妥30 mg/kg, 腹腔注射,每日一次).除对照组外均以低于急性致惊剂量的PTZ(40mg/kg,腹腔注射,每日一次)点燃大鼠,用行为学观察和脑电图确定癫痫存在,免疫组织化学方法 检测大鼠癫痫形成过程中不同时间点海马CA各区和齿状回神经细胞NF-κB活化,用图像分析系统分析对照组、非药物干预组和药物干预组三大组间海马神经细胞NF-κB活化的差异.结果 非药物干预组大鼠均于17d～22d点燃,而药物干预组PTZ点燃大鼠所需时间明显延长(于30d～35d点燃),且行为学惊厥程度和脑电痫样放电明显轻于非药物干预组.非药物干预组大鼠在行为学未出现惊厥,脑电图未出现痫样放电的点燃前潜伏期内,其海马CA各区、齿状回NF-κB活化的阳性神经细胞数明显增加,与对照组相比两者有显著性差异(P<0.05);药物干预组在与非药物干预组相应时间点的海马CA各区、齿状回NF-κB活化的阳性神经细胞明显减少,两者有显著性差异(P<0.05).结论 海马神经细胞活化是PTZ点燃大鼠癫痫形成的重要机制之一,苯巴比妥可通过抑制神经细胞活化,预防癫痫发生.     

甲基强的松龙抑制颅脑外伤后核因子κB的表达

目的探讨核因子κB(NF-κB)在人创伤性脑损伤(TBI)后挫伤皮层中的表达情况,同时观察甲基强的松龙对其表达的影响。方法挫伤区皮层的标本来自于24位TBI患者,分为两组,一组为TBI组,一组为甲基强的松龙治疗组,取样时间从伤后5h到24h。采用凝胶电泳迁移分析法(EMSA)测定NF-κB的活性,采用免疫组化技术检测NF-κBp65的表达情况。结果在人TBI后的挫伤区皮层中,NF-κB活性和表达强度明显上调,接受甲基强的松龙治疗的患者,其NF-κB活性和表达强度明显下降。结论NF-κB在人TBI后的挫伤区皮层中表达上调,提示其可能在TBI后的病理生理过程中起着重要作用,甲基强的松龙能抑制人TBI后挫伤区皮层中NF-κB的表达。     

Diagnostic Difficulties and Treatment Implications

Summary: Differentiation between types of epileptic seizures has been aided in recent years by the introduction of intensive neurodiagnostic techniques and the development of increasingly detailed classification systems. Paradoxically, these developments have not simplified the task of matching the appropriate antiepileptic drug to a particular seizure type. It is reasonable to assume that anticonvulsant drugs will have different effects on different types of seizures, but faulty, circular reasoning can enter the picture if one also assumes that responses of seizures to different drugs signify different seizure types. There are several examples of differential diagnoses that can fall prey to this problem, including the diagnosis between partial seizures with secondary generalization and generalized tonic-clonic seizures, and the diagnosis between complex partial seizures and absence seizures with automatisms, among others. Considerations of etiology in future classification systems can further complicate the problem: should one then choose an anticonvulsant drug on the basis of individual seizure type or on the basis of the type of epilepsy? Ramifications of this issue extend even to the drug approval process. Official sanction is not given for use of a drug for a seizure type not included in the original efficacy studies, even if later scientific evidence shows that seizure type to be related to a type that is included. New trials must be undertaken. These problems arise from how we choose to classify seizures.     

Cognitive Dysfunction Associated with Antiepileptic Drug Therapy

Summary: Epilepsy is frequently associated with cognitive dysfunction. However, the reasons for this correlation are unclear. Possible influential factors include patient age; duration, frequency, etiology, and type of seizures; hereditary factors; psychosocial issues; and antiepileptic drug (AED) therapy. Whereas many of these factors are beyond the physician's control, AED therapy is one element that can be addressed in treatment decisions by recognizing the potential cognitive effects of particular AEDs. For example, phenobarbital impairs memory and concentration; phenytoin affects attention, problem solving ability, and performance of visuomotor tasks. In contrast, carbamazepine may affect concentration, while valproate would appear to have minimal effects on cognition. Moreover, cognitive effects of AEDs are amplified with coadministration of multiple anticonvulsants (polytherapy). A review of studies on the cognitive effects of monotherapy with AEDs, as opposed to those of polytherapy, provides evidence that drug-related cognitive dysfunction can be reversed if patients are switched to a simpler therapeutic regimen. Future research should be directed toward developing reliable measures for assessing and monitoring cognition, and understanding the particular cognitive side effects of each AED. Physicians also need to revise their opinions about which side effects are "tolerable" for epileptic patients.     

Hepatic Considerations in the Use of Antiepileptic Drugs

Summary: Virtually all of the major antiepileptic drugs (AEDs) can cause hepatotoxicity, although fatal hepatic reactions are rare. The mechanisms, incidences, and risk profiles for such reactions differ from drug to drug. With carbamazepine and phenytoin, hepatotoxicity may be due to drug hypersensitivity. Although the profiles of patients at risk have not been well-defined for these two antiepileptic drugs, it would appear from reports in the literature that older adolescents and adults are at higher risk than children of developing serious or fatal hepatotoxicity. Once hepatotoxicity develops, mortality rates are 10–38% with phenytoin and 25% for carbamazepine. The risk profile for valproate fatal hepatotoxicity has been more clearly defined. Those at primary risk of fatal hepatic dysfunction are children under the age of 2 years who are receiving multiple anticonvulsants and also have significant medical problems in addition to severe epilepsy. The risk is considerably lower for patients over the age of 2 years on valproate monotherapy. In contrast to the risk profile with other AEDs, adults receiving valproate as monotherapy have the lowest risk of hepatotoxicity. Fatal hepatic dysfunction coincident with valproate may be the result of aberrant drug metabolism. Concomitant use of AEDs that induce microsomal P450 enzymes (e.g., phenytoin and phenobarbital) may enhance the production of a toxic metabolite, and hence the greater risk of hepatotoxicity with polypharmacy.     

Vascular Malformations and Epilepsy: Clinical Considerations and Basic Mechanisms

Summary: Vascular malformations (VMs) are associated with epilepsy. The natural history of the various VMs, clinical presentation, and tendency to provoke epilepsy determine treatment strategies. Investigations have probed the mechanisms of epileptogenesis associated with these lesions. Electrophysiologic changes are associated with epileptogenic cortex adjacent to VMs. Putative pathophysiologic mechanisms of epileptogenesis include neuronal cell loss, glial proliferation and abnormal glial physiology, altered neurotransmitter levels, free radical formation, and aberrant second messenger physiology.     

Carbamazepine Efficacy in Adults With Partial and Generalized Tonic-Clonic Seizures

Summary: Carbamazepine and phenytoin are drugs of choice in initial monotherapy for adult partial and secondarily generalized tonic-clonic seizures. These designations reflect the results of the Veterans Administration Epilepsy Cooperative Study Group of 1985. An earlier comparative study of carbamazepine and phenytoin by Ramsay and associates found both drugs equally effective in controlling new-onset seizures. Among the advantages of carbamazepine is that it causes relatively few cognitive and dysmorphic side effects. Its disadvantages are its unavailability in parenteral formulation and its metabolic autoinduction. The latter must be compensated for by planned dosage increases to maintain therapeutic plasma steady-state levels during the first 2 or 3 months of treatment. Carbamazepine is judged a drug of choice in the treatment of these secondarily generalized tonic-clonic seizures, and the drug of choice in children, adolescents, and women susceptible to the dysmorphic side effects associated with other anticonvulsant agents.     

Etiologic and Preventive Aspects of Epilepsy in the Child–Bridging the Gap Between Laboratory and Clinic

Summary: Four broad categories of basic phenomena are pertinent to developing ways to prevent epilepsy. These include mechanisms of epileptogenesis, ictal initiation and temporary entrainment by the seizure discharge of normally functioning brain, seizure propagation, and control mechanisms that function both to restrain the cascade of epileptic events culminating in a seizure and to arrest the epileptic event and restore the interictal state. In newborns and children, hypoxia-ischemia is a major factor leading to epileptogenesis, and several schemes are proposed to classify, quantify, and prevent hypoxic-ischemic encephalopathy. Control mechanisms must be better understood in order to develop prophylactic recommendations for epilepsy, and an experimental model of "kindling antagonism" may increase our understanding of these. Programs of prevention of seizures in children will evolve only if basic researchers and clinicians work productively together to develop an adequate understanding of factors important in epileptogenesis and antiepileptogenic control mechanisms.     

Epilepsy and anomalies of neuronal migration: MRI and clinical aspects

Neuronal migration disorders are the result of disturbed brain development. In such disorders, neurons are abnormally located. In diagnosing these conditions, magnetic resonance imaging is superior to any other imaging technique. This enables us to improve our knowledge of the clinical correlates of neuronal migration. With reference to migrational disorder, a retrospective study of all 303 patients with epileptic seizures referred for magnetic resonance imaging during a 3-year period was performed, 13 patients (aged 12-41, mean age 27) were identified. They represent 4.3% of the entire study group. Of the patients with known epilepsy, 6.7% and of the mentally retarded, 13.7% had migrational disorders. Four patients had schizencephaly as the dominant finding, one was classified as hemimegalencephaly, 2 had isolated heterotopias, and 6 had localized pachy- and/or poly-microgyria. The clinical pictures are complex. Ectopias of grey matter are recognised foci of epilepsy, but from an epileptological and a clinical viewpoint little attention has been given to these disorders. The present study shows that malmigration is not rare in epilepsy patients, especially not in the mentally retarded.     

Carbamazepine Efficacy and Utilization in Children

Summary: Carbamazepine is effective for preventing partial and generalized tonic-clonic seizures in children. Although absence epilepsies are more common in children than adults, an estimated 80% of children with epilepsy have seizure types or epilepsies that are potentially responsive to carbamazepine. The differential diagnosis of ictal staring is an especially important issue in children because absence and atypical absence seizures are more prevalent in children than adults. Age-related pharmacokinetic differences and drug interactions are major considerations in children. On average, children have higher clearance rates of carbamazepine, shorter half-lives, and higher ratios of carbamazepine-10, 11-epoxide to carbamazepine than adults. In addition, children with severe epilepsy are more likely to require multiple-drug therapy, which can lead to complex drug interactions. When carbamazepine is administered along with valproate, drug protein binding interactions can cause intermittent side effects.     

Predisposing and Causative Factors in Childhood Epilepsy

Summary: We review information from large studies of defined populations, examining the role of known factors and especially of prenatal and perinatal factors in contributing to nonfebrile seizure disorders of early childhood. We depend especially, but not exclusively, on the recently completed analyses from the Collaborative Perinatal Project of the National Institute of Neurological and Communicative Disorders and Stroke, the NCPP. About 4% of children in the NCPP who had at least one non-febrile nonsymptomatic seizure by the age of 7 years had a previous seizure during acute neurologic illness, such as meningitis or during the acute illness after trauma. Many such seizures should potentially be preventable. Of children with seizures, 10% had had a neonatal seizure and 13% had had a febrile seizure. Among the hundreds of prenatal and perinatal factors explored as predictors of childhood seizure disorders, the principal predictors identified were congenital malformations of the fetus, cerebral and noncerebral; family history of certain neurologic disorders; and neonatal seizures. In agreement with the British National Child Development Study, labor and delivery factors in the NCPP appeared to contribute very little to childhood seizure disorders. Maldevelopment, rather than damage at birth to an initially intact nervous system, appeared to be the more common mechanism. Most seizure disorders of early childhood remained unexplained by the large set of prenatal and perinatal characteristics examined.     

Anticonvulsant Drugs and Cognitive Function: A Review of the Literature

Summary: Alterations of cognitive function are separate from disturbances of behavior seen in association with epilepsy. The nature of the cognitive disability may to a certain extent depend on the seizure type. Partial seizures, mainly derived from a temporal lobe focus, impair memory tasks, while generalized seizures seem to have more effect on attentional abilities. A number of studies, reviewed in this paper, suggest that anticonvulsant drugs further impair cognitive function. Maximal impairments are seen in patients receiving polytherapy: rationalization of polytherapy improves cognitive abilities. Studies in children and adults have allowed differentiation of the effects of various commonly used antiepileptic agents. Maximal cognitive deficits are seen with. phenytoin, while phenobarbital and sodium valproate induce moderate disturbances, and carbamazepine seems relatively free from such toxicity. Further research is needed on the interrelationship between types of seizure disorders, types of anticonvulsant medications, and cognitive function.