IGF-1对MPP~+诱导PC12细胞凋亡的保护作用及其机制

目的探讨胰岛素样生长因子-1(IGF-1)对1-甲基-4-苯基吡啶离子(MPP+)诱导的PC12细胞凋亡的保护作用及机制。方法以250μmol/L的MPP+损伤PC12细胞作为帕金森病(PD)细胞模型,实验分组如下:空白对照组、MPP+组,IGF-1+MPP+组和抑制剂组。抑制剂组再分为:(1)空白对照组;(2)MPP+组;(3)IGF-1组;(4)IGF-1+MPP+组;(5)MPP++LiCL组;(6)IGF-1+MPP++LiCL组。孵育24h后采用AO-EB法检测细胞凋亡率;采用MTT法检测细胞存活率;孵育4h之后采用Western Blot免疫印迹法检测糖原合成酶激酶-3β(GSK-3β)、phospho-GSK-3β蛋白表达。结果(1)100nmol的IGF-1对MPP+处理的PC12细胞有保护作用,减少了MPP+所致的细胞凋亡。(2)LiCL起到了与IGF-1相似的对PC12细胞的保护作用。(3)总GSK-3β含量各处理组没有太大改变,但磷酸化的GSK-3β含量IGF-1组高于与MPP+单独处理组。结论IGF-1可减少MPP+所致的细胞凋亡,其保护作用与上调磷酸化的GSK-3β的表达相关。     

莱菔硫烷拮抗PC12细胞氧化应激损伤的机制

目的 探讨莱菔硫烷对体外1-甲基-4-苯基吡啶离子(MPP+)诱导的PC12细胞氧化损伤模型是否具有保护作用及其机制.方法 以MPP+损伤PC12细胞制备氧化损伤模型.不同浓度的莱菔硫烷加入培养基观察各组细胞生长情况.后续实验分成4组:正常对照组(A)、莱菔硫烷组(B)、MPP+损伤组(C)、莱菔硫烷预处理+MPP+损伤组(D).通过MTT比色法检测细胞活力,观察不同浓度莱菔硫烷预处理PC12细胞活力变化及不同分组PC12细胞活力变化;流式细胞术检测不同分组PC12细胞中细胞凋亡率的变化;免疫印迹法测定不同分组PC12细胞内转录因子相关因子2(Nrf2)、血红素加氧酶1(HO-1)及醌还原氧化酶1(NQ01)蛋白的表达变化.结果 A组细胞存活率(98.70％)与MPP+(500μmol/L)组(58.16％)相比差异有统计学意义(F =21.83,P＜0.05),D组细胞存活率明显提高.C组细胞凋亡率升高,D组细胞与C组相比差异有统计学意义,莱菔硫烷预处理后细胞凋亡率明显减低.C组Nrf2、HO-1、NQ01蛋白表达下降,D组Nrf2、HO-1、NQ01蛋白表达升高.结论 莱菔硫烷对MPP+诱导的PC12细胞损伤具有保护作用,莱菔硫烷对MPP+诱导的PC12细胞损伤的保护作用可能通过激活Nrf2-抗氧化反应元件通路途径实现.     

PI3 K/Akt信号在阿尔茨海默病样细胞中的作用及依达拉奉对其影响

目的探讨PI3K/Akt信号在β样淀粉蛋白(Aβ1-40)引起的PC12细胞凋亡中的作用及依达拉奉(MCI-186)对其影响。方法采用流式细胞学检测细胞凋亡,Western blot法检测磷酸化Akt及总Akt水平,观察MCI-186对其保护作用。结果模型组中各时间点Akt Ser473的磷酸化水平与对照组比较均降低而保护组各时间点Akt Ser473的磷酸化水平均有明显的升高(P<0.05),保护组中细胞凋亡率较模型组显著降低(P<0.01)。结论Aβ1-40主要通过抑制磷酸化Akt水平,进而诱导PC12细胞凋亡。MC-186通过激活PI3K/Akt信号传导途径,发挥拮抗细胞凋亡的作用,最终达到保护神经细胞的目的。     

14-3-3蛋白过表达减轻MPP+对PC12细胞的毒性损伤

目的 探讨14-3-3蛋白过表达对1-甲基-4-苯基吡啶离子(MPP+)诱导PC12细胞损伤的保护作用和可能的机制.方法 构建pcDNA3.1(+)-14-3-3真核表达质粒,转染PC12细胞,建立稳定过表达14-3-3蛋白细胞株;通过四甲基偶氮唑盐法(MTT法)、流式细胞术和酶标仪分别检测14-3-3蛋白过表达对MPP+诱导的PC12细胞存活力、凋亡率和SOD及谷胱甘肽过氧化物酶(GSH-Px)活性的影响.结果 14-3-3蛋白过表达显著增加PC12细胞SOD活性[质粒转染组(9.13±0.41)U/mg,MPP+组(6.45±0.52)U/mg]和GSH-Px活性[质粒转染组(89.66±3.42)μmol/mg,MPP+组(82.73±4.15)μmol/mg]、增强细胞活力[吸光度(A570):质粒转染组0.78±0.06,MPP+组0.54±0.07]、抑制细胞的凋亡(质粒转染组11.87%±3.26%,MPP+组36.30%±2.39%).结论 14-3-3蛋白过表达对MPP+的毒性有保护作用,这是通过增加SOD和GSH-Px的活性,减少氧化应激实现的.     

14-3-3蛋白过表达减轻1-甲基-4-苯基吡啶离子对PC12细胞的毒性(英文)

目的研究14-3-3蛋白过表达对1-甲基-4苯基吡啶离子(MPP )诱导的PC12细胞死亡的影响作用及其可能的机制。方法构建pcDNA3.1( )-14-3-3 真核表达质粒,用脂质体2000转染PC12细胞;Western blot技术检测PC12细胞中14-3-3蛋白、Bcl-2 蛋白, 和BAD蛋白的表达;然后分别用MTT法、酶标仪及流式细胞仪检测PC12细胞的活力、caspase的活性及PC12细胞的凋亡率。结果(1)将pcDNA3.1( )-14-3-3质粒转染PC12细胞3周后,14-3-3蛋白的表达显著增加;(2)MPP 诱导PC12细胞存活率的下降是剂量依赖性的,当MPP 的浓度达100 μmol/L时,PC12细胞的存活率丧失约50%;(3)caspase 的活性随着MPP 浓度的增加而增高,当MPP 浓度到达100 μmol/L时caspase的活性也到达最大值,而当MPP 浓度超过100 μmol/L时,caspase的活性急剧下降;(4)用100 μmol/L 的MPP 处理PC12细胞24 h后,PC12细胞的凋亡率为26.5%,14-3-3蛋白的过表达使PC12细胞的凋亡率下降到8.6%;(5)用100 μmol/L MPP 处理PC12细胞后,Bcl-2蛋白的表达趋于下调而BAD蛋白的表达上调,14-3-3蛋白的过表达能显著的增加Bcl-2蛋白的表达而使BAD蛋白的表达下调。结论14-3-3蛋白过表达通过上调Bcl-2蛋白的表达并下调BAD蛋白的表达,减少了MPP 诱导的PC12细胞的凋亡,从而发挥对PC12细胞的保护作用。这些结果可能为PD的治疗提供新的药物靶点。     

促红细胞生成素对1-甲基-4-苯基吡啶损伤的PC12细胞的保护作用(英文)

目的探讨促红细胞生成素(erythropoietin,EPO)对1-甲基-4-苯基吡啶离子(MPP+)诱导的PC12细胞变性损伤的保护作用及机制。方法用MPP+处理PC12细胞制作帕金森病细胞模型,采用四甲基偶氮唑蓝法检测暴露于不同浓度EPO后细胞的活性;流式细胞术与DNA断端原位标记法(terminal deoxynucleotidyl transferase dUTPnick end labeling, TUNEL)检测各组的细胞凋亡率;免疫印迹法检测不同处理组PC12细胞Bcl-2和Bax的表达,并采用荧光法观察不同处理组PC12细胞活性氧(reactive oxygen species,ROS)与线粒体膜电位水平以及caspase-3活性的变化。结果 MPP+可以使PC12细胞存活率下降,凋亡率增高;同时PC12细胞内ROS增多,线粒体膜电位下降。MPP+还可以明显地提高Bax/Bcl-2比值并激活caspase-3。而EPO可以抑制这些由MPP+引发的改变,并在1 U/mL时发挥最大保护作用。结论 EPO可抑制MPP+诱导的PC12细胞死亡,其作用机制可能与其自身抗氧化和抗凋亡的特性有关。     

H2O2预处理通过上调14-3-3蛋白表达减轻MPP+对PC12细胞的毒性作用

目的 探讨H2O2预处理(HPP)1-甲基4-苯基吡啶离子(MPP )诱导PC12细胞损伤的保护作用和可能的机制.方法 采用4甲基偶氮唑盐法(MTT法)、自动生化分析仪、4,6-二氨基-2-苯基吲哚(DAPI)染色法及免疫印迹(western blot)技术分别检测细胞活力、乳酸脱氢酶(LDH)活性、细胞凋亡及14-3-3蛋白的表达.结果 H2O2预处理能够上调14-3-3蛋白表达,增加PC12细胞活力(MPP 组52.46%±6.15%,HPP MPP 组83.78%±5.84%),抑制LDH的活性[MPP 组(37.31±3.99)U/L,HPP MPP 组(12.49±2.26)U/L];抑制细胞凋亡(MPP 48.72%±6.68%,HPP MPP 组17.56%±5.21%).结论 H202预处理能减轻MPP 对PCI2细胞的毒性损伤作用,这种保护作用是通过上调14-3-3蛋白的表达实现的.     

利福平对MPP+所致PC12细胞线粒体损伤的影响

目的 探讨利福平对1-甲基-苯基-吡啶离子(MPP+)诱导的大鼠嗜铬细胞瘤细胞株(PC12)细胞形态、线粒体结构的影响.方法 利用MPP+诱导分化PC12细胞建立帕金森病体外细胞模型;Hoechst33342荧光染色法检测细胞凋亡;透射电子显微镜观察各组细胞线粒体超微结构.结果 正常细胞组PC12细胞形态完整,线粒体结构完整清晰;MPP+作用后,凋亡细胞数量增多,核固缩、碎裂明显,线粒体空泡化明显,部分细胞见凋亡小体形成;利福平作用后,随着利福平浓度的增高,细胞凋亡程度及线粒体空泡化现象明显减轻,且存在浓度依赖性.结论 利福平可减轻MPP1+所致PC12细胞线粒体损伤的程度,推测可能是通过对线粒体的保护作用来减轻MPP+诱导的分化PC12细胞的凋亡,但其作用的具体途径还需进一步研究.     

姜黄素通过IGF-1/Akt/FoxO3a通路保护鱼藤酮诱导PC12细胞的PD模型

目的探究姜黄素(Cur)对鱼藤酮(Ro)诱导的PC12细胞损伤的保护作用及机制。方法建立鱼藤酮诱导的PC12细胞的帕金森病模型,利用姜黄素进行干预。实验分组为空白对照组,鱼藤酮模型组(终浓度:0.1μmol/L),姜黄素干预组(终浓度:0.5μmol/L、1.0μmol/L、5.0μmol/L、10μmol/L)。MTT比色法检测细胞活力,AO/EB荧光染色法观察细胞的凋亡情况,AnnexinⅤ-FITC/P双染检测细胞凋亡,Western-blot法检测细胞内IGF-1、Akt、FoxO3a的蛋白表达。结果 MTT结果显示:鱼藤酮组较对照组细胞活力明显降低,差异具有统计学意义(P<0.01),0.5μmol/L和1.0μmol/L姜黄素干预组可减轻0.1μmol/L鱼藤酮对PC12细胞增殖活力的影响,明显抑制了鱼藤酮对PC12细胞凋亡的诱导作用,与鱼藤酮组比较差异有统计学意义(P<0.01)Western-blot结果示:鱼藤酮组较对照组明显降低,差异具有统计学意义(P<0.01),0.5μmol/L和1.0μmol/L姜黄素干预组IGF-1、磷酸化的Akt(p-Akt)、磷酸化的FoxO3a(p-FoxO3a)表达与鱼藤酮组比明显升高,差异均有统计学意义(均P<0.01)。以上结果均显示5.0μmol/L和10μmol/L姜黄素干预组与鱼藤酮组比较差异无统计学意义(P>0.05);结论适宜浓度的姜黄素对鱼藤酮诱导PC12细胞损伤的PD模型具有保护作用,其保护作用呈浓度依赖性,其保护作用的机制可能与激活IGF-1/Akt/FoxO3a通路有关。     

胰岛素受体磷酸化增加对MPP＋诱导的PC12细胞凋亡的影响

目的:研究胰岛素抗MPP 诱导PC12细胞凋亡中胰岛素受体(IR)的变化。方法:应用半定量逆转录聚合酶链式反应(RT-PCR)测定胰岛素抗MPP 诱导PC12细胞凋亡过程中IRmRNA的基因表达,免疫沉淀Western印迹分析技术测定相同条件下IR的蛋白表达,应用IR自身磷酸化的特异阻断剂HNMPA-AM3,通过MTT法观察PC12细胞生存率的改变、瞬转IR质粒后再次观察细胞生存率的改变及进一步通过免疫沉淀Western印迹分析技术检测IR蛋白质磷酸化水平。结果:IR磷酸化程度的变化与细胞生存率的变化有关,HNMPA-AM3可阻断胰岛素对MPP 诱导的PC12细胞的抗凋亡作用,IR可增强胰岛素的抗凋亡作用。结论:IR磷酸化增加可抵抗MPP 诱导的PC12细胞的凋亡。     

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.     

Classification of methods in transcranial Electrical Stimulation (tES) and evolving strategy from historical approaches to contemporary innovations

Transcranial Electrical Stimulation (tES) encompasses all methods of non-invasive current application to the brain used in research and clinical practice. We present the first comprehensive and technical review, explaining the evolution of tES in both terminology and dosage over the past 100 years of research to present day. Current transcranial Pulsed Current Stimulation (tPCS) approaches such as Cranial Electrotherapy Stimulation (CES) descended from Electrosleep (ES) through Cranial Electro-stimulation Therapy (CET), Transcerebral Electrotherapy (TCET), and NeuroElectric Therapy (NET) while others like Transcutaneous Cranial Electrical Stimulation (TCES) descended from Electroanesthesia (EA) through Limoge, and Interferential Stimulation. Prior to a contemporary resurgence in interest, variations of transcranial Direct Current Stimulation were explored intermittently, including Polarizing current, Galvanic Vestibular Stimulation (GVS), and Transcranial Micropolarization. The development of these approaches alongside Electroconvulsive Therapy (ECT) and pharmacological developments are considered. Both the roots and unique features of contemporary approaches such as transcranial Alternating Current Stimulation (tACS) and transcranial Random Noise Stimulation (tRNS) are discussed. Trends and incremental developments in electrode montage and waveform spanning decades are presented leading to the present day. Commercial devices, seminal conferences, and regulatory decisions are noted. We conclude with six rules on how increasing medical and technological sophistication may now be leveraged for broader success and adoption of tES.     

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.     

Neonatal Seizures: Problems in Diagnosis and Classification

Summary: The clinical identification of neonatal seizures is critical for the recognition of brain dysfunction; however, diagnosis is often difficult because of the poorly organized and varied nature of these behaviors. Current classification systems are limited in their ability to communicate motor, autonomic, and electroencephalo-graphic features of seizures precisely and to provide a basis for uniform effective diagnosis, therapy, and determination of prognosis. Recent investigations of neonates, utilizing bedside electroencephalographic/polygraphic/ video monitoring techniques, have provided the basis for improved diagnosis and classification of seizures in the newborn. These studies have demonstrated that not all clinical phenomena currently considered to be seizures require electrocortical epileptiform activity for their initiation or elaboration. In addition, the specific clinical character of the phenomena considered to be seizures, the clinical state of the infant, and the character of the EEG indicate the probable pathophysiological mechanisms involved and suggest probable etiologies, prognosis, and therapy. Similarities between animal models that demonstrate reflex physiology and neonates with motor automatisms and tonic posturing suggest that these clinical behaviors may not be epileptic in origin but, rather, primitive movements of progression and posture mediated by brainstem mechanisms. Although not all clinical behaviors currently considered to be neonatal seizures may have similar pathophysiological mechanisms, they are clinically significant because they all indicate brain dysfunction.     

Valproate Monotherapy in the Management of Generalized and Partial Seizures

Summary: For decades, therapeutic tradition has promoted the concept of polypharmacy in the management of epilepsy. In recent years, however, studies have shown that, for most patients, monotherapy can provide comparable or better seizure control than administration of multiple anticonvulsants, while diminishing the potential for adverse reactions, drug interactions, and poor compliance. Valproate is an important monotherapeutic agent that is highly effective in the control of idiopathic primary and secondarily generalized epilepsies, and partial seizures that do not generalize. Comparative studies have found that valproate is at least as effective as phenytoin and carbamazepine in the treatment of generalized and partial seizures. Given the similar efficacy, other factors such as pharmacokinetics and side effects may therefore determine anticonvulsant selection for monotherapy.     

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.     

Un nouveau cadre conceptuel de travail pour la psychiatrie

In an attempt to place psychiatric thinking and the training of future psychiatrists more centrally into the context of modern biology, the author outlines the beginnings of a new intellectual framework for psychiatry that derives from current biological thinking about the relationship of mind to brain. The purpose of this framework is twofold. First, it is designed to emphasize that the professional requirements for future psychiatrists will demand a greater knowledge of the structure and functioning of the brain than is currently available in most training programs. Second, it is designed to illustrate that the unique domain which psychiatry occupies within academic medicine, the analysis of the interaction between social and biological determinants of behavior, can best be studied by also having a full understanding of the biological components of behavior.