N-乙酰半胱氨酸抗谷氨酸诱导海马神经元损伤的研究

目的　观察N-乙酰半胱氨酸(N- acetylcysteine,NAC)对不同浓度谷氨酸(Glutamte,Glu)诱导海马神经元损伤的影响,探讨其作用机制,评价毒性作用。方法　采用台盼蓝活细胞拒染与TUNEL法比较不同浓度NAC预处理3d给药与细胞毒性暴露后快速给药对10 0μmol/ L、5 0 0μm ol/ L Glu诱导体外培养海马神经元损伤的影响,并与MK- 80 1比较;利用激光扫描共聚焦显微镜(L SCM)观测细胞内Ca2 浓度变化;采用台盼蓝活细胞拒染、原子力显微镜(AFM)及细胞内酯酶活性判定方法评价NAC毒性。结果　NAC可降低10 0μmol/ L Glu诱导的海马神经元死亡率,以预处理组为佳,1m mol/ L NAC预处理保护效果类似于10μmol/ L MK - 80 1;NAC对5 0 0μm ol/ L Glu诱导的海马神经元损伤无保护作用。1mm ol/ L NAC预处理抑制Glu诱导的神经元Ca2 内流。经10 0 mmol/ L NAC作用的细胞虽然形态完整,但台盼蓝染色蓝染,失去对Glu毒性的反应性;AFM扫描见神经元细胞膜皱缩;培养基Ca2 经Fluo- 3(AM)标记后L SCM下无激发荧光。结论　NAC对轻度Glu细胞毒性损伤有保护作用,预防性用药效果更优越。认为抑制Glu诱导的神经元Ca2 内流为其保护机制之一。高浓度NAC具有固定作用     

N-乙酰半胱氨酸防止帕金森病鼠黑质神经元凋亡

目的：研究N．乙酰半胱氨酸(N—acetylcystein，NAC)对1-甲基4-苯基-1，2，3，6-四氢吡啶(1-methyl-4-phe-ny-1．1，2，3，6-tetrahydropyridine，MPTP)诱导的帕金森病小鼠黑质神经元凋亡的保护机制。方法：采用MPTP制备帕金森病(Parkinson disease，PD)小鼠模型，应用生化技术检测黑质区域谷胱甘肽(GSH)浓度及超氧化物歧化酶(SOD)活力，用尼氏(Nissl)染色、TH组化染色、活化型Caspase3组化染色及TUNEL染色观察黑质神经元的损害情况，并计算神经元的凋亡率，同时应用蛋白免疫印迹法检测黑质神经元磷酸化JNK及磷酸化c—Jun蛋白表达水平。另经NAC预处理该模型后，对上述指标进行检测。结果：NAC预处理能提高黑质区域GSH的浓度及降低SOD活力，减轻PD鼠黑质致密带Nissl阳性神经元和TH阳性神经元的脱失现象，减少磷酸化JNK及磷酸化c—Jun蛋白表达水平，使活化型Caspase3表达减少并降低黑质神经元的凋亡率。结论：NAC能减少MPTP诱导的小鼠黑质神经元凋亡，其机制与抗氧化及阻断JNK细胞凋亡通路的激活有关。     

N-乙酰半胱氨酸防止帕金森病鼠黑质神经元凋亡

目的:研究N-乙酰半胱氨酸(N-acetylcystein,NAC)对1-甲基-4-苯基-1,2,3,6-四氢吡啶(1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine,MPTP)诱导的帕金森病小鼠黑质神经元凋亡的保护机制.方法:采用MPTP制备帕金森病(Parkinson disease,PD)小鼠模型,应用生化技术检测黑质区域谷胱甘肽(GSH)浓度及超氧化物歧化酶(SOD)活力,用尼氏(Nissl)染色、TH组化染色、活化型Caspase 3组化染色及TUNEL染色观察黑质神经元的损害情况,并计算神经元的凋亡率,同时应用蛋白免疫印迹法检测黑质神经元磷酸化JNK及磷酸化c-Jun蛋白表达水平.另经NAC预处理该模型后,对上述指标进行检测.结果:NAC预处理能提高黑质区域GSH的浓度及降低SOD活力,减轻PD鼠黑质致密带Nissl阳性神经元和TH阳性神经元的脱失现象,减少磷酸化JNK及磷酸化c-Jun蛋白表达水平,使活化型Caspase 3表达减少并降低黑质神经元的凋亡率.结论:NAC能减少MPTP诱导的小鼠黑质神经元凋亡,其机制与抗氧化及阻断JNK细胞凋亡通路的激活有关.     

N-乙酰半胱氨酸对PC12细胞的保护作用研究

目的探讨N-乙酰半胱氨酸（NAC）对PC12细胞的保护作用及其机制。方法采用神经毒素1μmol/L鱼藤酮处理PC12细胞24h,并在处理前30min加入500μmol/L的NAC进行干预,流式细胞术检测PC12细胞的凋亡率和活性氧水平,比色法检测还原型谷胱甘肽（GSH）水平。结果PC12细胞经1μmol/L鱼藤酮处理24h后,细胞凋亡率达41.9%,细胞内活性氧水平较对照组显著提高,而GSH水平显著下降（P〈0.05）;NAC干预后,能够明显抑制鱼藤酮的细胞毒性作用,与鱼藤酮组相比,细胞凋亡率和活性氧水平显著降低,GSH含量明显增加（P〈0.05）。结论在帕金森病（PD）的细胞模型中,通过NAC的干预,能够明显保护PC12细胞,其保护机制与抗氧化能力有关。     

N-乙酰半胱氨酸对大鼠颅脑损伤后炎性因子表达的影响

目的探讨N-乙酰半胱氨酸（NAC）对大鼠颅脑损伤后促炎症细胞因子白细胞介素-6（IL-6）和抗炎症细胞因子白细胞介素-10（IL-10）的表达水平的影响及其脑保护作用。方法采用Feeney法制作颅脑损伤模型,将75只雄性Wistar大鼠随机分为假手术组、颅脑创伤组及NAC干预组。酶联免疫吸附测定（ELISA）分析假手术组、NAC干预组及颅脑创伤组IL-6和IL-10血清表达水平的变化,并用干湿重法测定脑组织含水量。结果颅脑创伤组IL-6表达时相为高峰期时IL-10表达水平也较高,二者存在正相关关系;而NAC干预组IL-6表达水平较颅脑创伤组自3h后相应时间点明显降低（P〈0.01）,IL-10在3h后相应时间点明显升高（P〈0.01）;NAC干预组伤侧脑组织含水量在3d和5d时较假手术组相应时间点脑组织含水量下降,且具有统计学意义（P〈0.05）,余时间点伤侧脑组织含水量虽有下降但无统计学意义（P〉0.05）。结论NAC可能通过抑制颅脑损伤后促炎因子的过度表达,同时可提高抗炎因子的表达水平,从而减轻脑创伤后过度炎性反应,减轻脑水肿,发挥其脑保护作用。     

N-甲基-D-门冬氨酸受体重组肽抗血清对谷氨酸兴奋毒性导致神经元坏死和凋亡的保护作用

目的 观察N-甲基-D-门冬氯酸受体(NMDAR，NR)主亚基(NR1)M3M4环重组肽自身抗血清对不同浓度谷氨酸诱导的神经元死亡的保护作用。方法 用NR1 M3M4环重组肽免疫Balh／C(H-2^d)小鼠制备抗血清，用锥虫蓝染色法和原位末端标记(TUNEL)法观察抗血清对原代培养海马神经元兴奋毒性坏死和凋亡的保护效应。结果 在高浓度谷氨酸(500μmoL／L)条件下，阳性抗血清可以使神经元坏死减少16％；在低浓度谷氨酸(50μmol／L)作用下，阳性抗血清保护可使神经元凋亡率减少13％。结论 NMDAR重组肽自身免疫抗血清具有抗兴奋毒性作用，这一结论为免疫防治兴奋毒性脑损伤策略的建立提供了坚实的体外基础。     

N-乙酰半胱氨酸对脑缺血诱导信号转导与转录激活子-3的磷酸化及DNA结合活性的影响

目的 研究抗氧化剂N-乙酰半胱氨酸对全脑缺血诱导海马组织信号转导与转录激活子-3(STAT3)的激活及DNA结合活性的影响。方法 采用SD雄性大鼠四动脉结扎(4-VO)全脑缺血模型，以及腹腔注射给药的方法。运用抗磷酸化STAT3抗体做免疫印迹(IB)检测海马核抽提物磷酸化STAT3的变化；以及电泳迁移率改变实验(EMSA)分析核内STAT3 DNA结合活性的变化。结果 全脑缺血不同时间导致核内STAT3磷酸化水平及DNA结合活性的持续增高；缺血前20min腹腔注射抗氧化剂N-乙酰半胱氨酸能明显抑制其增高。结论 全脑缺血所致STAT3的磷酸化水平及DNA结合活性的增高与氧化应激有一定的关系。     

脑损伤后N-乙酰天冬氨酰谷氨酸肽酶抑制的神经保护

目的 探索颅脑损伤后N-乙酰天冬氨酰谷氨酸(NAAG)肽酶抑制的神经保护效应.方法 将20只SD大鼠随机分成4组后制作中度液压颅脑损伤模型.伤后3个时间点(即时,8 h,16 h)分别经腹腔注射新型NAAG肽酶抑制剂ZJ-43(各组剂量:0,50,100,150 mg/kg).伤后24 h处死动物取脑组织行Fluoro-Jade B组织荧光染色以及GFAP免疫组化染色.通过立体细胞计数着重观察大鼠海马CA2/3区退变神经元及正常胶质细胞的数量变化.结果 ZJ-43能显著减少颅脑损伤后的神经元退变(P＜0.01),其中小剂量处理组(50 mg/kg)保护作用最佳,还能同时显著减少儋颅脑损伤后的胶质细胞丢失(P＜0.05).结论 阻断NAAG肽酶活性能有效放大内源性递质NAAG的神经保护作用,从而阻断谷氨酸兴奋毒性的病理进程,有望成为治疗颅脑损伤的新策略.     

PACAP对谷氨酸引起海马神经元损伤的保护作用

目的研究垂体腺苷酸环化酶激活肽（ＰＡＣＡＰ）对谷氨酸引起的海马神经元损伤的保护作用及其受体机制。方法海马神经元体外培养７ｄ,给予谷氨酸。结果当谷氨酸是０．１～１．０ｍｍｏｌ／Ｌ时,随着剂量的增加,神经元的存活率逐渐降低;１０－９ｍｏｌ／Ｌ～１０－１３ｍｏｌ／Ｌ的ＰＡＣＡＰ,能减轻谷氨酸引起的海马神经元损伤;ＰＡＣＡＰⅠ型受体特异性拮抗剂ＰＡＣＡＰ６－３８能抑制ＰＡＣＡＰ减轻谷氨酸对海马神经元损伤作用。结论ＰＡＣＡＰ具有减轻谷氨酸引起的海马神经元损伤的作用,该作用是由ＰＡＣＡＰⅠ型受体介导的。     

N-乙酰半胱氨酸在治疗神经精神障碍中的应用

正N-乙酰半胱氨酸(N-acetylcysteine,NAC)作为临床治疗药物已达数十年之久,主要应用于对乙酰氨基酚过量、慢性阻塞性肺疾病、对比剂肾病等方面的治疗~([1])。NAC生物学特性多样,涉及抗氧化应激、抗炎、促进线粒体修复、参与神经递质传递等,广泛参与神经细胞的生理过程~([1])。近年来,有研究发现NAC对部分神经精神障碍有良好的治疗效果,如病理性赌博~([2])、强迫症~([3])、自闭症~([4])等。这不仅为     

海马神经元兴奋性毒性模型的建立及其意义

目的探讨不同浓度谷氨酸对海马神经元的损伤作用,流式细胞仪在建立理想的兴奋性毒性模型中的应用。方法在体外原代培养10d的海马神经元中分别加入不同浓度的谷氨酸(100、200、400、600、800μmol/L),24h后相差显微镜下观察细胞形态变化,用MTT法检测存活率和流式细胞仪检测凋亡率以评定谷氨酸对海马神经元的损伤程度。结果不同浓度的谷氨酸组与对照组的细胞存活率差异有显著性(P<0.01),并呈浓度依赖性,随着谷氨酸浓度的升高,神经元的存活率降低;谷氨酸终浓度(100、200、400μmol/L)组的细胞凋亡率与对照组比较差异有显著性(P<0.01);600和800μmol/L谷氨酸组的细胞凋亡率与对照组比较差异无显著性(P>0.05),但细胞凋亡率随着谷氨酸浓度的增加而降低。结论过高浓度的谷氨酸导致细胞急性坏死而非迟发性凋亡,运用流式细胞仪检测体外培养海马神经元凋亡率是一种特异性高的检测方法,值得推广。     

Calbindin overexpression buffers hippocampal cultures from the energetic impairments caused by glutamate

A dramatic rise in free cytosolic calcium concentration is thought to be a central event in the pathogenesis of glutamate excitotoxicity in neurons. We have previously demonstrated that gene transfer of the calcium-binding protein calbindin D28k via a Herpes simplex amplicon vector decreases the rise in intracellular calcium and promotes cell survival following glutamatergic challenge. This study explores the effect of calbindin transgene expression on cellular metabolism following glutamate excitotoxicity. Because excitotoxic insults are often energetic in nature, and because calcium sequestering and extrusion place heavy energy demands on a cell, we hypothesized that calbindin overexpression may help preserve cellular energy levels during an insult. We overexpressed calbindin in primary hippocampal cultures, using a Herpes simplex amplicon vector system. We found that calbindin overexpression protected neurons from the decline in ATP levels, mitochondrial potential and metabolic rate following a glutamatergic insult. These results indicate that calbindin expression helps preserve cellular energy state following glutamate excitotoxicity. This illustrates the energetic load placed on neurons by increased free cytosolic calcium and may help explain the neuroprotective effects of calbindin.     

米诺环素对戊四氮致疒间大鼠海马神经元凋亡的保护作用

目的探讨米诺环素对神经元凋亡的保护作用及与剂量的关系。方法采用戊四氮(PTZ)建立的癫疒间大鼠模型,用灌胃法给不同剂量的米诺环素后麻醉大鼠,灌注取脑进行石蜡切片制备及免疫组化检测,采用HPIAS-1000高清晰度彩色病理图文分析系统进行图像分析,观察大鼠海马区细胞凋亡变化。结果对照组与PTZ组比较,对照组凋亡数目少(P<0.05);MT1组与PTZ组比较,细胞凋亡无差异(P﹥0.05);MT2组与PTZ组比较,MT2组细胞凋亡数少(P<0.05);MT3组与PTZ组比较,MT3组细胞凋亡多(P<0.05)。各干预组之间比较,MT2组细胞凋亡较MT3组、MT1组都少(P<0.05)。结论米诺环素在适当的浓度范围内有神经元保护作用。     

Propofol administration reduces hippocampal neuronal damage induced by kainic acid in rats

Abstract

The goal of this study was to determine whether propofol has protective effect against kainic acid (KA)I. ndu~ed excftotoxicity. Administration of propofol (25 mg kg-⁷ i.p.) was done 2 h, before KA (10 mg kg-¹ I.P.), Immedlatelyafte:1 and 2h, 4h, 6h, and 12 h afte~ the KAI and twice daily for an additional three days. Neuronal cell death In CA 1 an.d .CA3 subsector of hIppocampus was evaluated quantitatively four days after KA. The KA and propofol-Injected rats had a greater number of surviving neuronal cells than did KA (and vehicle)-Injected rats. Our results suggest that propofol holds potential for the protection of neuronal cells agaInst KA-induced excitotoxicity. [Neural Res 1999; 21: 225-228]     

盐酸法舒地尔对慢性脑低灌注损伤大鼠海马细胞的保护作用

目的 观察Rho激酶抑制剂盐酸法舒地尔(hydroxy fasudil, HF)对慢性低灌注脑缺血所致大鼠海马神经细胞损伤的保护作用。方法 采用永久性结扎大鼠双侧颈总动脉(permanent occlusion of the bilateral CCA, 2VO)制备大鼠慢性不完全性全脑缺血模型,将SD大鼠随机分为假手术组、脑缺血模型组和HF治疗组,运用Morris 水迷宫行为学方法检测大鼠空间学习记忆能力; 用HE染色观察海马组织形态学改变。结果 Morris 水迷宫检测发现模型组大鼠学习记忆能力受损,与假手术组比较逃避潜伏期延长、空间辨别能力下降; 组织学观察模型组大鼠海马CA1细胞发生丢失,组织结构异常。连续给予盐酸法舒地尔30 d能改善大鼠学习记忆功能,减少脑缺血所致的大鼠海马神经细胞丢失。结论 盐酸法舒地尔可减少慢性脑缺血所致的大鼠海马神经元的丢失,改善学习记忆功能。     

Chemical adrenalectomy reduces hippocampal damage induced by kainic acid

Glucocorticoids (GCs), the adrenal steroids secreted during stress, have numerous catabolic effects which include damage to neurons of the hippocampus, a principal neural target site for the steroids. In the rat, the extent of GC exposure over the lifespan is a major determinant of the rate of hippocampal neuron death during aging. GCs also modulate the severity of hippocampal damage in the rat following insults such as seizure or hypoxia-ischemia. As evidence, exogenous GCs exacerbate, while adrenalectomy attenuates hippocampal damage after these insults. Thus, it is possible that diminution of endogenous GC secretion might protect the human hippocampus after similar neurological insults; adrenalectomy under such circumstances is obviously not a viable clinical option. We demonstrate the protective effects of transient chemical adrenalectomy with the GC synthesis inhibitor, metyrapone. Rats were microinfused with the excitotoxin kainic acid in order to induce status epilepticus seizures; this insult caused a significant GC stress-response. Attenuation of that response with metyrapone reduced the CA3 hippocampal damage produced by kainic acid. Metyrapone did not change the intensity of seizures, but rather, apparently, changed the capacity of neurons to withstand the seizure. Thus, metyrapone, which is used safely and efficaciously in other clinical contexts, might prove protective of the brain following seizure in the human.     

Increased susceptibility of glutathione peroxidase-1 transgenic mice to kainic acid-related seizure activity and hippocampal neuronal cell death

Glutathione peroxidase (GSHPx) has been demonstrated in several in vivo studies to reduce both the risk and severity of oxidatively-induced tissue damage. The seizure-inducing neurotoxin kainic acid (KA) has been suggested to elicit its toxic effects in part via generation of oxidative stress. In this study, we report that expression of elevated levels of murine GSHPx-1 in transgenic mice surprisingly results in increased rather than decreased KA susceptibility including increased seizure activity and neuronal hippocampal damage. Isolated transgenic primary hippocampal culture neurons also display increased susceptibility to KA treatment compared with those from wildtype animals. This could be due to alterations in the redox state of the glutathione system resulting in elevated glutathione disulfide (GSSG) levels which, in turn, may directly activate NMDA receptors or enhanced response of the NMDA receptor.     

The effect of glutamate receptor blockers on glutamate release following spinal cord injury. Lack of evidence for an ongoing feedback cascade of damage --> glutamate release --> damage --> glutamate release --> etc

It is widely hypothesized that excitotoxicity of released glutamate following a CNS insult is propagated by the cyclic cascade: glutamate release --> damage --> glutamate release --> further damage --> etc. We tested this hypothesis by determining the effects of attempting to interrupt the loop by administering glutamate receptor antagonists and Na(+)-channel blockers on glutamate release following spinal cord injury (SCI). The effects of administering the NMDA receptor blockers MK-801 and memantine, the AMPA/kainate receptor blockers NBQX and GYKI 52466, the AMPA receptor desensitization blocker cyclothiazide and the sodium channel blockers riluzole, mexiletine and QX-314 on post-SCI were determined. Agents were administered into the site of injury by direct injection, by microdialysis or systemically. None of these agents had an appreciable effect on glutamate release following SCI. Thus, it is unlikely that the above cascade produces significant secondary glutamate release and ongoing damage following SCI, although such cascades may worsen other CNS insults. We attribute our results to overwhelming effects of much greater release by direct mechanical damage and reversal of transport following SCI.     

出生5 d大鼠海马神经元缺氧耐受性研究

目的建立出生5d大鼠海马神经元原代培养方法，并研究该神经元的缺氧耐受性。方法改进出生5d大鼠海马神经元原代培养方法，分离海马时分为充氧组与对照组，培养过程中倒置显微镜和细胞核因子（NF）免疫组织化学法观察细胞生长和形态。原代培养7d后，分别对出生5d大鼠海马神经元和出生1d大鼠海马神经元进行12h、24h的缺氧处理（0％02、5％C02、95％N2），MTT法检测细胞存活情况。结果（1）充氧组中培养的出生5d大鼠海马神经元生长状态要优于对照组中培养的神经元。（2）缺氧12h出生1d以及5d大鼠海马神经元存活率分别为（81．5±2．3）％和（89，4±2，2）％（P〈0．01）；缺氧24h二者存活率分别为（75．0±2．8）％和（85．0±2．2）％（P〈0．01）。5d海马神经元缺氧耐受能力优于1d大鼠海马神经元。结论海马神经元分离培养过程中充氧有利于神经元的原代培养，出生5d大鼠海马神经元缺氧耐受力强于出生1d大鼠海马神经元。