Par-4反义寡核苷酸对谷氨酸诱导PC12细胞STAT3活性下调的抑制作用

目的研究Par-4反义寡核苷酸拮抗谷氨酸对PC12细胞中信号转导子和激活子3(STAT3)活性的下调作用及其抗凋亡意义.方法脂质体将Par-4反义寡核苷酸转染PC12细胞.谷氨酸诱导PC12细胞凋亡.吖啶橙/溴化乙锭荧光染色观察PC12细胞形态.流式细胞分析评价凋亡百分率.Western blot测定Par-4的蛋白表达量,凝胶迁移改变实验测定STAT3的DNA结合力.结果谷氨酸诱导PC12细胞中蛋白表达上调,Par-4反义寡核苷酸呈剂量依赖性地拮抗其上调(P＜0.01).谷氨酸诱导PCl2细胞中STAT3的DNA结合力下调,Par-4反义寡核苷酸拈抗其下调(P＜0.01).Par-4反义寡核苷酸拮抗谷氨酸诱导的PC12细胞凋亡.如予Jak/STAT3信号通路阻断剂AG-490预处理,则其拮抗作用被下调.结论Par-4反义寡核苷酸拈抗谷氨酸诱导的PC12细胞凋亡,其机制可能与STAT3活化有关.     

20008/神经生长因子通过PTEN保护谷氨酸诱导的海马神经元凋亡

目的：探讨NGF保护谷氨酸（Glu）诱导海马神经元凋亡中PTEN的作用。方法：新生（< 24 hr）大鼠海马神经元培养7天后,随机分为对照组、谷氨酸组（0.2 mM）和NGF组（10、50、100、200μg•L -1）采用LDH和MTT法检测NGF对Glu损伤细胞活力的影响,采用DAPI染色法检测海马神经元凋亡,采用RT-PCR法和Western blot法测定PTEN mRNA及蛋白表达。结果：NGF可明显提高Glu损伤的海马神经元的细胞活力,减少海马神经元的凋亡和PTEN的表达。结论：NGF对Glu诱导的海马神经元损伤有保护作用,其机制可能与减少PTEN表达,抑制神经元凋亡有关。     

c—fos反义寡核苷酸对谷氨酸处理培养海马神经元的保护作用

目的 :探讨反义寡核苷酸c fos对谷氨酸处理培养海马神经元的保护作用。方法 :应用MTT法 (四甲基偶氮唑盐微量酶反应比色法 )检测c fos反义寡核苷酸在不同浓度和时间对谷氨酸处理原代培养海马神经细胞的光密度值。结果 :c fos反义寡核苷酸在不同浓度和时间下对谷氨酸处理原代培养海马神经细胞光密度值均有增加。结论 :c fos反义寡核苷酸对谷氨酸毒性损伤的培养海马神经元有保护作用     

谷氨酸诱导转Bax基因PC12细胞凋亡及 神经生长因子的保护作用

目的探讨谷氨酸诱导转Bax基因PC12细胞凋亡及神经生长因子（NerveGrowthFactor,NGF）的保护作用。方法应用脂质体介导细胞转染方法进行Bax基因转染PC12细胞,结合流式细胞术和TUNEL法检测了谷氨酸处理前后转Bax基因PC12细胞的凋亡及NGF的保护作用。结果与对照组相比,谷氨酸处理转Bax基因PC12细胞凋亡峰增高,TUNEL阳性标记细胞增多;用NGF处理后该组细胞凋亡峰减低,TUNEL阳性标记细胞数减少。差异均有显著意义。结论谷氨酸处理转染Bax基因PC12细胞凋亡增加,NGF可以保护谷氨酸诱导的转染Bax基因PC12细胞凋亡。     

谷氨酸诱导转Bax基因PCl2细胞凋亡及神经生长因子的保护作用

目的 探讨谷氨酸诱导转Bax基因PC12细胞细胞凋亡及神经生长因子（NerveGrowth Factor,NGF)的保护作用。方法 应用脂质体介导细胞转染方法进行Bax基因转染PC12细胞,结合流式细胞术和TUNEL法检测了谷氨酸处理前后转Bax基因PC12细胞的凋亡及NGF的保护作用。结果 与对照组相比,谷氨酸处理转Bax基因PC12细胞凋亡峰增高,TUNEL阳性标记细胞增多。用NGF处理后该组细胞凋亡峰减低,TUNEL阳性标记细胞数减少,差异均有显著意义。结论 谷氧酸处理转染Bax基因PC12细胞凋亡增加,NGF可以保护谷氨酸诱导的转染Bax基因PC12细胞凋亡。     

睾酮对Aβ25-35诱导PC12细胞凋亡保护机制的研究

目的 探讨睾酮对Aβ25- 35诱导PC12细胞凋亡的保护作用机制.方法 MTT法观察睾酮对Aβ25-35诱导PC12细胞凋亡后细胞活性的影响;Hochest—PI染色观察睾酮对Aβ25- 35诱导PC12细胞凋亡形态学的影响;Western免疫印迹法和Real — time PCR法观察睾酮对Aβ25- 35诱导PC12细胞凋亡相关调控因子bcl-XL、Bax蛋白及mRNA表达的影响.结果 与对照组相比,睾酮预保护后可以明显抑制Aβ25-35诱导PC12细胞凋亡后细胞活性及细胞形态学变化,并上调bcl-XL蛋白及mRNA、下调Bax蛋白及mRNA的表达,雄激素受体拮抗剂氟他胺干预后可以明显抑制睾酮的保护效应.结论 睾酮保护Aβ25-35诱导的PC12细胞凋亡活动,其潜在作用机制可能是通过AR介导的基因信号传导通路在蛋白表达和基因转录水平上抑制Bax、上调bcl-XL的表达实现.     

局灶性脑缺血再灌注大鼠海马CA1区神经元凋亡研究

目的 观察大鼠局灶性脑缺血再灌注(ischemia reperfusion,I/R)损伤后海马CA1区神经元凋亡、TUNEL阳性细胞变化,以及凋亡相关蛋白Bcl-2与Bax蛋白的表达情况.方法 将健康雄性SD (Sprague-Dawley)大鼠随机分为假手术组和I/R组,每组再分为缺血再灌注后3、6、12、24、48、72 h亚组.应用免疫组化方法检测再灌注后不同时间点大鼠海马CA1区神经元凋亡基因Bcl-2和Bax蛋白的表达及Bcl-2/Bax比值变化,采用原位细胞凋亡检测(TUNEL)技术检测凋亡阳性细胞数.结果 各组非缺血侧相应区域神经元胞质中Bcl-2均有微弱表达.I/R组缺血侧海马CA1区于再灌注3 h开始出现Bcl-2和Bax蛋白微弱表达,随再灌注时间延长神经元内Bcl-2表达逐渐增强,再灌注24 h后Bcl-2表达达高峰,假手术组与I/R组比较差异有统计学意义(P<0.05).结论 I/R损伤后海马CA1区神经元不仅存在变性坏死,还存在明显的细胞凋亡且细胞凋亡在大鼠I/R损伤中发挥重要作用;I/R可诱导海马CA1区细胞凋亡基因Bcl-2和Bax蛋白表达,且其表达呈一定规律.     

大鼠局灶性脑缺血再灌注后海马Bcl-2、Bax蛋白的表达

目的 探讨大鼠局灶性脑缺血再灌注后Bcl-2、Bax蛋白在海马表达的变化.方法 线栓法制作大鼠局灶性脑缺血再灌注模型,应用免疫组化染色检测Bcl-2、Bax蛋白表达,应用TUNEL法检测海马区细胞凋亡.结果 缺血再灌注2h后海马神经元Bcl-2、Bax蛋白开始表达,Bcl-2蛋白12h达高峰,Bax蛋白12h～24h达高峰,之后开始下降.再灌注2h后海马凋亡细胞开始表达,随着再灌注时间的延长,其表达不断增加.Bcl-2/ Bax的比率在再灌注开始时升高,再灌注12h达高峰,随后开始下降.结论 凋亡是脑缺血再灌注损伤的重要形式之一,Bcl-2/ Bax的改变与缺血再灌注后海马的神经元存亡有关,缺血再灌注可导致海马神经元凋亡.     

促红细胞生成素对体外帕金森病模型细胞凋亡及Bax蛋白表达的影响

目的 观察促红细胞生成素(EPO)对体外帕金森病模型细胞凋亡及Bax蛋白表达的影响.方法 体外培养多巴胺能神经元细胞加入6-OHDA建立帕金森病细胞模型,分为对照组、6OHDA组和EPO+ 6-OHDA组,采用TH免疫组织化学方法和TUNEL法观察体外培养7d时细胞凋亡情况,检测Bax蛋白表达.结果 与对照组比较,6-OHDA组存在明显的细胞凋亡和Bax蛋白高表达(P＜0.05)；与6-OHDA组比较,EPO+ 6-OHDA组细胞凋亡明显减少,Bax蛋白表达降低(P＜0.05).结论 促红细胞生成素能减少6-羟基多巴诱导的神经元细胞凋亡,降低Bax蛋白表达.     

高糖诱导大鼠海马神经元细胞模型建立及细胞凋亡的影响

目的通过不同葡萄糖浓度和不同作用时间诱导SD大鼠海马神经元,建立稳定的糖尿病脑病细胞模型,探讨高糖对海马神经元凋亡情况的影响。方法 (1)海马神经元的原代培养及纯度鉴定。(2)最适高糖浓度探索:CCK-8法检测海马神经元各组细胞活性。(3)最适浓度下高糖作用时间的探索:Western blot检测海马神经元细胞Bcl-2、Bax的表达情况。(4)最适浓度和作用时间下,流式细胞术检测细胞的凋亡率。结果 (1)成功培养海马神经元,神经元细胞经鉴定纯度达85%以上。(2) 45 mmol/L组海马神经元存活率均 80%。(3) 45 mmol/L-48 h为最适作用时间组,细胞内Bcl-2表达下降、Bax表达升高(P 0. 01)。(4)最适高糖组细胞凋亡率显著升高(P 0. 01)。结论高糖浓度为45 mmol/L、作用时间48 h为理想的糖尿病脑病细胞模型,且高糖通过影响Bcl-2、Bax的表达导致海马神经元凋亡率升高。     

Down-regulation of Cl- pump ClP55 subunit induced enhancement of glutamate neurotoxicity in cultured rat hippocampal neurons

To test whether the increased intracellular Cl- concentration ([Cl-]i) is responsible for the enhanced glutamate toxicity, antisense oligonucleotide of ClP55, a Cl- -ATPase/pump associated protein, was transfected in cultured rat hippocampal neurons. Neuronal [Cl-]i in the antisense oligonucleotide-transfected culture increased to a level 3- to 4-fold higher than that in control. Glutamate exposure (10 microM, 10 min) increased neuronal apoptosis and decreased Akt-pS473 level in the antisense oligonucleotide-transfected neurons, but not in control or sense oligonucleotide-transfected ones, suggesting the responsibility of elevated [Cl-]i in the enhancement of glutamate neurotoxicity.     

The endoplasmic reticulum stress-responsive protein GRP78 protects neurons against excitotoxicity and apoptosis: suppression of oxidative stress and stabilization of calcium homeostasis

The 78-kDa glucose-regulated protein (GRP78) is localized in the endoplasmic reticulum (ER), and its expression is increased by environmental stressors in many types of nonneuronal cells. We report that levels of GRP78 are increased in cultured rat hippocampal neurons exposed to glutamate and oxidative insults (Fe2+ and amyloid beta-peptide) and that treatment of cultures with a GRP78 antisense oligodeoxynucleotide increases neuronal death following exposure to each insult. GRP78 antisense treatment enhanced apoptosis of differentiated PC12 cells following NGF withdrawal or exposure to staurosporine. Pretreatment of hippocampal cells with 2-deoxy-d-glucose, a potent inducer of GRP78 expression, protected neurons against excitotoxic and oxidative injury. GRP78 expression may function to suppress oxidative stress and stabilize calcium homeostasis because treatment with GRP78 antisense resulted in increased levels of reactive oxygen species and intracellular calcium following exposure to glutamate and oxidative insults in hippocampal neurons. Dantrolene (a blocker of ER calcium release), uric acid (an antioxidant), and zVAD-fmk (a caspase inhibitor) each protected neurons against the death-enhancing action of GRP78 antisense. The data suggest that ER stress plays a role in neuronal cell death induced by an array of insults and that GRP78 serves a neuroprotective function.     

孕酮对原代培养海马神经细胞谷氨酸损伤的保护作用

目的观察孕酮对原代培养海马神经细胞谷氨酸损伤的保护作用。方法取新生大鼠海马神经细胞进行体外原代培养,建立谷氨酸对培养海马神经细胞兴奋毒性损伤模型,在相差显微镜下观察孕酮处理前后神经细胞形态变化,乳酸脱氢酶活性测定试剂盒检测细胞培养上清乳酸脱氢酶漏出量。结果孕酮组神经细胞部分形态保持较好,生长情况明显好于谷氨酸组,乳酸脱氢酶漏出量较谷氨酸组减少。结论孕酮对体外培养的海马神经细胞谷氨酸兴奋毒性损伤具有保护作用。     

Antisense knockdown of the glial glutamate transporter GLT-1 exacerbates hippocampal neuronal damage following traumatic injury to rat brain

Traumatic injury to rat brain induced by controlled cortical impact (CCI) results in chronic neuronal death in the hippocampus. In the normal brain, glutamate transporters actively clear the glutamate released synaptically to prevent receptor overactivation and excitotoxicity. Glutamate transporter 1 (GLT-1) is the most abundant and active glutamate transporter, which mediates the bulk of glutamate uptake. CCI injury significantly decreased GLT-1 mRNA (by 49-66%, P < 0.05) and protein (by 29-44%, P < 0.05) levels in the ipsilateral hippocampus, compared with either the respective contralateral hippocampus or the sham-operated control, 24-72 h after the injury. CCI injury in rats infused with GLT-1 antisense oligodeoxynucleotides (ODNs) exacerbated the hippocampal neuronal death and mortality, compared with the GLT-1 sense/random ODN-infused controls. At 7 days after the injury, hippocampal neuronal numbers were significantly lower in the CA1 (reduced by 32%, P < 0.05), CA2 (by 45%, P < 0.01), CA3 (by 68%, P < 0.01) and dentate gyrus (by 31%, P < 0.05) in GLT-1 antisense ODN-infused rats, compared with the GLT-1 sense/random ODN-infused controls. This study suggested a role for GLT-1 dysfunction in promoting the hippocampal neuronal death after traumatic brain injury.     

谷氨酸对分化PC12细胞的氧化损伤及人参皂苷Rg1的保护作用

目的观察不同浓度的谷氨酸对PC12细胞的氧化损伤,探讨人参皂苷Rg1对谷氨酸兴奋性毒性的拮抗作用。方法用MTT法检测细胞活性及MDA、GSH、GSH-Px测定,检测谷氨酸对PC12细胞的损害,用人参皂苷Rg1做保护研究。结果谷氨酸可导致PC12细胞活力明显下降,MDA、GSH、GSH-Px测定结果与正常对照组和人参皂苷Rg1保护组有明显差异(P<0．01)。结论人参皂苷Rg1对谷氨酸所致的氧化损伤有保护作用。     

降钙素基因相关肽对缺氧时大鼠海马培养神经元c—fos表达的影响

采用免疫组化（ABC）方法，观察缺氧诱导体外培养大鼠海马神经元c-fos的表达及降钙素基因相关肽（CGRP）的影响。结果显示，缺氧后海马神经元中Fos-免疫反应（Fos—IR）阳性胞核百分率随缺氧时间的延长而逐渐增多，图像分析的结果显示，缺氧后Fos—IR阳性胞核的平均失密度亦随缺氧时间的延长而逐渐增强。经CGRP孵育的海马神经元缺氧后Fos-IR阳性胞核的百分率和Fos-IR阳性胞核的平均光密度均明显低于非CGRP孵育组。本结果表明，缺氧能诱导体外培养海马神经元。c-fos的表达，神经肽CGRP能抑制缺氧海马神经元c-fos的表达。提示CGRP对海马神经元缺氧损伤可能具有一定保护作用。     

去铁敏对体外培养的大鼠海马神经元谷氨酸毒性的保护作用

目的 探讨去铁敏对体外培养的海马神经元谷氨酸损伤的保护作用及可能机制.方法 建立体外培养的大鼠海马神经元谷氨酸毒性模型.细胞分为去铁敏组、对照组.采用形态学观察、Hoechst 33342染色、乳酸脱氢酶(LDH)检测评价细胞损伤情况.生化法检测羟自由基、丙二醛变化.用显微荧光测量技术监测神经元内钙信号的动态变化.结果 去铁敏组较对照组神经元形态保持良好.去铁敏组及对照组细胞核固缩率分别为14%±6%和58%±6%(t=8.98,P＜0.01),LDH分别为(36.42±8.99)U/L和(68.06±11.26)U/L(t=3.25,P＜0.05),羟自由基分别为(34.21±4.23)U/L和(47.06±8.79)U/L(t=3.11,P＜0.05),丙二醛分别为(12.26±2.78)nmol/mg和(28.86±5.19)nmol/mg(t=4.88,P＜0.01).结论 去铁敏能减轻谷氨酸导致的神经元损伤,其可能的机制与去铁敏减少谷氨酸导致的神经元内钙浓度的升高及自由基水平有关.     

Telomerase protects developing neurons against DNA damage-induced cell death.

In mitotic cells, telomerase adds repeats of a DNA sequence (TTAGGG) to the ends of chromosomes (telomeres) thereby maintaining their length and preventing cellular senescence. We recently reported that the catalytic subunit of telomerase (TERT) is expressed in neuronal progenitor cells and in early postmitotic neurons in the developing rodent brain. We now report that TERT can protect cultured PC12 cells and embryonic hippocampal neurons against death induced by DNA damage. Overexpression of TERT in PC12 cells increases their resistance to the topoisomerase inhibitors camptothecin and etoposide. Hippocampal neurons in which TERT levels are decreased using antisense technology exhibit increased vulnerability to the DNA-damaging agents. Emerging findings suggest that DNA damage may trigger the death of neurons during brain development and in neurodegenerative disorders. Our data therefore suggest roles for TERT in modulating such cell deaths.