p38信号通路对缺氧下大鼠星形胶质细胞增殖凋亡的影响及机制研究

目的探讨p38信号通路对缺氧下星形胶质细胞增殖凋亡的影响。方法从新生2 d的大鼠的脑组织分离原代星形胶质细胞,将细胞分为缺氧组、缺氧+p38抑制剂组和正常组,各组细胞培养12 h后,Western blot检测细胞中p38、p-p38蛋白表达;24 h后CCK8实验和流式细胞术分别检测细胞的增殖及凋亡情况,Western blot检测Bcl-2、Bax、Cleaved Caspase3蛋白表达。结果缺氧组p-p38蛋白表达显著高于正常组,而缺氧+SB203580组p-p38蛋白表达显著低于缺氧组(P0.01);缺氧组细胞存活率及Bcl-2蛋白表达均显著低于正常组,细胞凋亡率及Bax、Cleaved Caspase3蛋白表达均显著高于正常组(P0.01);缺氧+SB203580组细胞存活率及Bcl-2蛋白表达均显著高于缺氧组,细胞凋亡率及Bax、Cleaved Caspase3蛋白表达均显著低于缺氧组(P0.01)。结论 p38信号通路的激活降低了缺氧下星形胶质细胞增殖并促进细胞的凋亡,而抑制p38信号通路可提高细胞的增殖及抑制细胞的凋亡。     

抗衰老酶1-p53信号通路在吸入麻醉致原代海马神经元细胞凋亡中的神经保护作用

目的:探讨抗衰老酶1(sirtuin 1,SIRT1)在七氟醚(sevoflurane,Sev)联合一氧化二氮(N_2O)吸入麻醉导致的原代海马神经元细胞凋亡中的作用。方法:原代海马神经元予以1.3%Sev联合50%N_2O吸入麻醉(对照组给予50%O_2)处理2 h,或吸入麻醉前分别予以SIRT1拮抗剂sirtinol(50μmol/L)、salermide(50μmol/L)或激动剂resveratrol(100μmol/L)处理24 h。24 h后收集细胞,采用蛋白质印迹法检测Bax、剪切型半胱氨酸蛋白酶3(cleaved caspase-3,c-caspase-3)、剪切型聚腺苷酸二磷酸核糖转移酶[cleaved poly (ADP-ribose) polymerase,c-PARP]、磷酸化组蛋白H2A家族成员X(phosphorylated H2A histone family member X,γ-H2AX)、SIRT1和乙酰化p53[acetylated p53(lysine 381),acetyl-p53]蛋白水平,采用免疫荧光染色法检测c-caspase-3、SIRT1和acetyl-p53蛋白的分布及表达情况。结果:Sev联合N_2O吸入麻醉显著上调原代海马神经元中促凋亡蛋白Bax、c-caspase-3、c-PARP及DNA损伤相关指标γ-H2AX的表达水平(P0.05);同时麻醉组SIRT1蛋白表达水平也显著升高,而acetyl-p53表达水平显著降低(P0.05)。吸入麻醉处理前给予SIRT1拮抗剂sirtinol或salermide预处理可抑制吸入麻醉引起的SIRT1蛋白表达上调,但增加了促凋亡蛋白Bax、c-caspase-3、c-PARP及DNA损伤指标γ-H2AX的表达(P0.05);SIRT1激动剂预处理则呈现相反的结果(P0.05)。结论:Sev联合N_2O吸入麻醉引起的SIRT1-p53信号通路激活可抑制其所致的原代海马神经元细胞凋亡。     

高压氧对脑缺血再灌注海马神经元Bcl-2和Bax蛋白表达的影响

目的观察高压氧(HBO)作用下脑缺血再灌注海马CA1区神经元Bcl-2和Bax蛋白表达的变化情况,进一步研讨高压氧治疗脑缺血再灌注损伤、减轻神经元凋亡从而发挥保护作用的机制。方法沙土鼠20只,采用随机数字法将实验动物分为正常对照组、缺血组、0.15MPaHBO治疗组、0.25MPaHBO治疗组,0.25MPa压力空气(hyperbaricair,HBA)对照组,每组4只动物。采用“双侧颈总动脉阻断法”前脑缺血模型,缺血20min后再灌注3d,并用0.15MPa和0.25MPa压力的高压氧治疗(60min/d,连续3d)后,应用免疫组化LSAB方法,观察高压氧对海马CA1区神经元凋亡相关基因Bcl-2和Bax的蛋白表达的影响。结果沙土鼠脑缺血再灌注3d组海马CA1区大量神经元表达Bax蛋白,并且神经元发生凋亡,未见神经元表达Bcl-2蛋白;高压氧治疗组则大量神经元表达Bcl-2蛋白,并且0.25MPa高压氧治疗组比0.15MPa高压氧治疗组变化更显著,而各组表达Bax蛋白的神经元数目无明显变化,但高压氧治疗组Bax蛋白阳性的神经元形态正常。结论HBO暴露可诱导大量神经元表达Bcl-2蛋白,对Bax蛋白表达则无明显作用,使Bcl-2和Bax蛋白表达的比值增高,从而起到保护神经元的作用,这可视为HBO治疗脑缺血性损伤减少神经元凋亡的机制之一。     

大鼠缺氧复氧损伤神经元钙敏感受体表达水平及其与神经元凋亡的相关性分析

目的分析缺氧复氧损伤神经元钙敏感受体表达水平及其与神经元凋亡的相关性。方法取新生SD大鼠(出生1 d)脊髓神经元,随机分为A组(正常对照,未进行任何处理)、B组(建立缺氧复氧损伤模型)、C组(缺氧复氧损伤+激动剂GdCl_3)、D组(缺氧复氧损伤+抑制剂NPS-2390)。通过免疫荧光技术对各组大鼠脊髓神经元中钙敏感受体的表达定位进行检测,并用Western blotting法对各组钙敏感受体及凋亡相关蛋白B淋巴细胞瘤-2(Bcl-2)、Bcl-2相关X蛋白(Bax)、半胱氨酸天冬氨酸蛋白酶-3(Caspase-3)表达水平进行检测,通过激光共聚焦显微镜对细胞内游离钙的变化进行检测,同时用TUNEL法对各组细胞凋亡情况进行检测。结果 B组钙敏感受体和细胞内游离钙的表达水平较A组显著升高(P 0. 01),C组钙敏感受体和细胞内游离钙表达水平较B组显著升高(P 0. 01),D组钙敏感受体和细胞内游离钙表达水平较B组显著下降(P 0. 01)。B组细胞凋亡比率较A组显著升高,C组细胞凋亡比率较B组显著升高,D组细胞凋亡比率较B组显著下降(P 0. 05)。B组凋亡相关蛋白Bcl-2的表达水平较A组显著下降,Bax和Caspase-3的表达水平较A组显著升高(P 0. 05); C组Bcl-2的表达水平较B组显著下降,Bax和Caspase-3的表达水平较B组显著升高(P 0. 05); D组Bcl-2的表达水平较B组显著升高,Bax和Caspase-3的表达水平较B组显著下降(P 0. 05)。结论在大鼠缺氧复氧损伤模型中,钙敏感受体在脊髓神经元中的表达水平升高,细胞内游离钙增多,脊髓神经元细胞凋亡比率升高,凋亡相关蛋白的表达水平升高。     

p75TNFR激活型单克隆抗体对脑创伤小鼠炎症反应的保护作用

目的 通过单克隆抗体激活p75TNFR信号通路,观察对小鼠脑创伤后关键炎症信号转导通路p38MAPK活化水平和炎症因子表达水平的影响,并探讨其作用机制.方法 参照Feeney等的自由落体法制作小鼠创伤性颅脑损伤模型,运用Western-blot方法检测炎症信号通路中关键分子p38MAPK变化,采用ELISA方法检测注射了D8F2的小鼠血清中炎症因子IL-6、TNF-α和IL-1β水平的变化.结果 创伤后TNF-α、IL-1β、IL-6水平均明显升高,治疗组则低于创伤组,且更快恢复至正常水平.创伤后体内p38MAPK迅速激活至较高水平,治疗组则低于创伤组,且下降更快.结论 在小鼠脑创伤模型中D8F2能通过抑制p38MAPK活化,抑制炎症因子水平的升高,对脑创伤小鼠炎症损害起保护作用.     

粉防己碱诱导人肺腺癌细胞SPC-A-1凋亡的机制

目的:观察粉防己碱(tetrandrine,Tet)对人肺腺癌细胞SPC-A-1凋亡的影响机制.方法:培养人肺腺癌细胞SPC-A-1,Hoechst 33258染色观察细胞凋亡形态改变,流式细胞仪观察Tet对凋亡率和细胞周期的影响;Western-blot测定p53、p21及Bax的表达.结果:Hoechst 33258染色、流式细胞仪及琼脂糖凝胶电泳均显示Tet明显诱导细胞凋亡,引起G0/G1期阻滞,Western-blot显示Tet明显提高p53、p21及Bax表达.结论:Tet可诱导人肺腺癌细胞SPC-A-1凋亡,其机制可能与上调p53、p21及Bax表达有关.     

吡咯喹啉醌对培养的海马神经元衰老的影响

目的 观察吡咯喹啉醌(PQQ)对D-半乳糖(D-gal)致培养大鼠海马神经细胞衰老损伤的影响.方法 体外原代培养新生大鼠海马神经元,用大剂量D-gal诱致海马神经元老化损伤,用PQQ做保护研究,镜F观察神经元的形态变化,测海马神经细胞自由基的水平,流式细胞仪测细胞的凋亡率,免疫组化测Bax蛋白的表达.结果 体外培养8 d的海马神经细胞用D-gal处理后,细胞自由基水平升高,细胞的死亡率增加,Bax表达增强;预先给予PQQ处理后,细胞内自由基水平以及Bax的表达下降,细胞死亡率下降.结论 PQQ能廷缓D-gal引起的培养大鼠海马神经细胞的衰老.     

褐藻多糖硫酸酯通过调控PCNA-AS1表达对宫颈癌细胞增殖和凋亡的影响

目的探讨褐藻多糖硫酸酯对宫颈癌细胞增殖和凋亡的影响及可能的作用机制。方法体外培养宫颈癌Hela细胞,褐藻多糖硫酸酯作用Hela细胞后,细胞计数试剂盒-8(CCK-8)法检测Hela细胞抑制率,流式细胞术检测细胞凋亡率,蛋白印迹(Western Blot)法检测细胞中细胞周期蛋白D1(CyclinD1)、p21、B淋巴细胞瘤-2(Bcl-2)和B淋巴细胞瘤-2相关蛋白(Bax)蛋白表达水平,实时荧光定量PCR(RT-qPCR)检测细胞中PCNA-AS1基因表达水平。转染PCNA-AS1小干扰RNA或PCNA-AS1过表达载体至Hela细胞后,上述相同方法观察干扰PCNA-AS1表达或过表达PCNA-AS1的同时使用褐藻多糖硫酸酯处理对Hela细胞抑制率、凋亡率及CyclinD1、p21、Bax和Bcl-2的蛋白表达的影响。结果褐藻多糖硫酸酯作用Hela细胞后,细胞抑制率、凋亡率及p21和Bax蛋白表达水平显著升高(P0.05),CyclinD1和Bcl-2蛋白及PCNA-AS1表达水平显著降低(P0.05)。干扰PCNA-AS1表达后,Hela细胞抑制率、凋亡率及p21和Bax蛋白表达水平显著升高(P0.05),CyclinD1和Bcl-2蛋白表达水平显著降低(P0.05)。过表达PCNA-AS1的同时使用褐藻多糖硫酸酯作用Hela细胞,细胞抑制率、凋亡率及p21和Bax蛋白表达水平显著降低(P0.05),CyclinD1和Bcl-2蛋白表达水平显著升高(P0.05)。结论褐藻多糖硫酸酯可抑制宫颈癌Hela细胞增殖并诱导细胞凋亡,其作用机制可能与下调PCNA-AS1表达有关。     

利拉鲁肽对神经母细胞瘤细胞牵张损伤的神经保护作用

目的探讨胰高血糖素样肽-1类似物利拉鲁肽对神经母细胞瘤细胞(SH-SY5Y)牵张损伤的神经保护作用。方法本实验以SH-SY5Y细胞作为研究对象,首先采用MTT实验筛选最适宜的利拉鲁肽处理浓度,然后利用可控性细胞损伤装置(CIC-II)建立细胞牵张损伤模型。将实验分为3组,即对照组、细胞牵张损伤组、利拉鲁肽治疗组(1μM利拉鲁肽处理SH-SY5Y细胞24 h)。乳酸脱氢酶(LDH)法检测各组细胞毒性;蛋白免疫印迹实验检测凋亡相关蛋白Bax、抗凋亡蛋白Bcl-2的表达和Caspase-3的表达水平。结果 MTT实验显示,利拉鲁肽处理SH-SY5Y细胞适宜的保护性浓度为1μM。LDH实验显示,与对照组相比,牵张损伤组LDH漏出量显著增多;与细胞损伤组相比,利拉鲁肽治疗组细胞LDH漏出量明显降低(P0.05);蛋白免疫印迹实验显示:与对照组相比,细胞损伤组Bax表达水平显著增强,Bcl-2表达显著减少,Caspase-3表达明显增高,细胞凋亡百分比显著增高;与细胞损伤组相比,利拉鲁肽治疗组Bax和Caspase-3蛋白表达水平降低(P0.05),Bcl-2表达显著增多(P0.01),细胞凋亡百分比显著降低。结论利拉鲁肽可以减轻细胞损伤引起的LDH释放水平,利拉鲁肽能显著降低损伤细胞的凋亡。利拉鲁肽通过抑制细胞凋亡进而发挥其神经保护作用。     

抗血小板整合素β3抗体诱导内皮细胞凋亡机制的研究

目的:探讨抗血小板整合素β3抗体对人脐静脉血管内皮细胞(HUVEC)的损伤及其相关机制。方法:收集36例慢性免疫性血小板减少症患者的血清,通过流式细胞术和单克隆抗体特异性俘获血小板抗原技术(MAIPA)筛选出含抗整合素β3抗体的患者血清。用抗整合素β3血清处理HUVEC后,乳酸脱氢酶(LDH)活性测定法检测HUVEC损伤情况,流式细胞术检测HUVEC凋亡情况,逆转录实时荧光定量PCR(RT-q PCR)检测HUVEC凋亡相关基因Bax表达情况,Western blot检测细胞凋亡相关信号通路蛋白Akt和相关蛋白Bax的表达情况。用抗整合素β3血清结合Akt激活剂SC79处理HUVEC后,LDH活性测定法检测HUVEC损伤情况,流式细胞术检测HUVEC的凋亡情况,RT-q PCR检测HUVEC凋亡相关基因Bax的表达情况。结果:从36份患者血清中筛选出5份含抗整合素β3抗体血清,用这些血清处理HUVEC后,细胞外LDH活性增加(P<0.05),细胞凋亡比例增加(P<0.05),Bax蛋白和mRNA表达水平上调(P<0.05),p Akt蛋白表达下调(P<0.05)。抗整合素β3血清结合SC79处理HUVEC后,与单独使用抗整合素β3血清处理组相比,细胞外LDH活性显著降低(P<0.05),HUVEC凋亡比例显著下降(P<0.05),Bax基因表达下降(P<0.05)。结论:抗整合素β3抗体在体外能够引起HUVEC的损伤和凋亡,其作用机制可能与抑制Akt信号通路有关,且Akt激活剂SC79能够在体外抑制抗整合素β3抗体引起的HUVEC损伤和凋亡。     

Mitochondrial Fragmentation Is Involved in Methamphetamine-Induced Cell Death in Rat Hippocampal Neural Progenitor Cells

Methamphetamine (METH) induces neurodegeneration through damage and apoptosis of dopaminergic nerve terminals and striatal cells, presumably via cross-talk between the endoplasmic reticulum and mitochondria-dependent death cascades. However, the effects of METH on neural progenitor cells (NPC), an important reservoir for replacing neurons and glia during development and injury, remain elusive. Using a rat hippocampal NPC (rhNPC) culture, we characterized the METH-induced mitochondrial fragmentation, apoptosis, and its related signaling mechanism through immunocytochemistry, flow cytometry, and Western blotting. We observed that METH induced rhNPC mitochondrial fragmentation, apoptosis, and inhibited cell proliferation. The mitochondrial fission protein dynamin-related protein 1 (Drp1) and reactive oxygen species (ROS), but not calcium (Ca²⁺) influx, were involved in the regulation of METH-induced mitochondrial fragmentation. Furthermore, our results indicated that dysregulation of ROS contributed to the oligomerization and translocation of Drp1, resulting in mitochondrial fragmentation in rhNPC. Taken together, our data demonstrate that METH-mediated ROS generation results in the dysregulation of Drp1, which leads to mitochondrial fragmentation and subsequent apoptosis in rhNPC. This provides a potential mechanism for METH-related neurodegenerative disorders, and also provides insight into therapeutic strategies for the neurodegenerative effects of METH.     

A new poly(ADP-ribose) polymerase inhibitor, FR261529 [2-(4-chlorophenyl)-5-quinoxalinecarboxamide], ameliorates methamphetamine-induced dopaminergic neurotoxicity in mice

Methamphetamine (METH) administration in mice, results in a chronic dopamine (DA) depletion associated with nerve terminal damage, with DA oxidation and generation of reactive oxygen species (ROS) primarily mediating this neurotoxicity. The oxidative stress induced by METH putatively activates nuclear enzyme poly(ADP-ribose) polymerase (PARP), with excessive PARP activation eventually leading to cell death. In this study, we show that prevention of PARP activation by treatment with FR261529 [2-(4-chlorophenyl)-5-quinoxalinecarboxamide], the compound that was recently identified as a novel PARP inhibitor (IC50 for PARP-1 = 33 nM, IC50 for PARP-2 = 7 nM), protects against both ROS-induced cells injury in vitro and METH-induced dopaminergic neuronal damage in an in vivo Parkinson's disease (PD) model. In PC12 cells, exposure of hydrogen peroxide or METH markedly induced PARP activation, and treatment with FR261529 (1 microM) significantly reduced PARP activation and attenuated cell death. In the mouse METH model, METH (15 mg/kg x 2 i.p., 2 h apart) intoxication accelerated DA metabolism and oxidation in the striatum, with subsequent cell damage in nigrostriatal dopaminergic neurons after 4 days. Oral administration of FR261529 (10 or 32 mg/kg) attenuated the damage of dopaminergic neurons via marked reduction of PARP activity and not via changes in dopamine metabolism or body temperature. These findings indicate that the neuroprotective effects of a novel PARP inhibitor, FR261529, were accompanied by inhibition of METH-induced PARP activation, suggesting that METH induces nigrostriatal dopaminergic neurodegeneration involving PARP activation and also orally active and brain-penetrable PARP inhibitor FR261529 could be a novel attractive therapeutic candidate for neurodegenerative disorders such as PD.     

Vitamin E prevents hypobaric hypoxia-induced mitochondrial dysfunction in skeletal muscle

In the present study, the effect of vitamin E (alpha-tocopherol) on mice skeletal muscle mitochondrial dysfunction and oxidative damage induced by an in vivo acute and severe hypobaric hypoxic insult (48 h at a barometric pressure equivalent to 8500 m) has been investigated. Male mice (n=24) were randomly divided into the following four groups (n=6): control (C), hypoxia (H), vitamin E (VE; 60 mg/kg of body weight intraperitoneally, three times/week for 3 weeks) and hypoxia+VE (HVE). A significant increase in mitochondrial protein CGs (carbonyl groups) was found in the H group compared with the C group. Confirming previous observations from our group, hypoxia induced mitochondrial dysfunction, as identified by altered respiratory parameters. Hypoxia exposure increased Bax content and decreased the Bcl-2/Bax ratio, whereas Bcl-2 remained unchanged. Inner and outer mitochondrial membrane integrity were significantly affected by hypoxia exposure; however, vitamin E treatment attenuated the effect of hypoxia on mitochondrial oxidative phosphorylation and on the levels of CGs. Vitamin E supplementation also prevented the Bax and Bcl-2/Bax ratio impairments caused by hypoxia, as well as the decrease in inner and outer mitochondrial membrane integrity. In conclusion, the results suggest that vitamin E prevents the loss of mitochondrial integrity and function, as well as the increase in Bax content, which suggests that mitochondria are involved in increased cell death induced by severe hypobaric hypoxia in mice skeletal muscle.     

Bcl-2,Bax和线粒体膜蛋白在一氧化氮供体诱导HL-60细胞凋亡中的改变

本研究探讨外源性一氧化氮 (NO)供体硝普钠 (SNP)对HL 6 0细胞诱导凋亡的可能机制。将HL 6 0细胞与SNP在体外培养 ,用DNA片段原位末端标记法 (TUNEL)测定原位细胞凋亡率 ;用流式细胞仪测定细胞DNA倍体和周期分析及Bcl 2、Bax、线粒体膜蛋白表达率的变化。结果表明 :SNP可诱导HL 6 0细胞凋亡 ,两者之间有明显的量效和时效关系。 1.0mmol/LSNP作用 4 8小时后 ,HL 6 0细胞的凋亡率分别为亚二倍体峰 (4 2 .2± 3.5 ) % ,TUNEL测定凋亡细胞率为 (5 2 .5± 7.6 ) % ,显著高于空白对照组和同浓度的高铁氰化钾 (PFC)组 ;Bax基因蛋白和线粒体膜蛋白 (APO2 .7)表达增加 ,bcl 2基因蛋白表达降低。Bax、Bcl 2和APO2 .7的表达率与SNP两者之间也有明显的量效和时效关系。结论 :外源性一氧化氮供体诱导HL 6 0细胞凋亡过程中 ,线粒体膜蛋白表达显著上调并伴随Bax和Bcl 2蛋白的表达改变。     

Competitive and noncompetitive antagonists at N-methyl-D-aspartate receptors protect against methamphetamine-induced dopaminergic damage in mice.

The administration of methamphetamine (METH) to experimental animals results in damage to nigrostriatal dopaminergic neurons. We have demonstrated previously that the excitatory amino acids may be involved in this neurotoxicity. For example, several compounds which bind to the phenyclidine site within the ion channel linked to the N-methyl-D-aspartate (NMDA) receptor protected mice from the METH-induced loss of neostriatal tyrosine hydroxylase activity and dopamine content. The present study was conducted to characterize further the role of the excitatory amino acids in mediating the neurotoxic effects of METH. The administration of three or four injections of METH (10 mg/kg) every 2 hr to mice produced large decrements in neostriatal dopamine content (80-84%) and in tyrosine hydroxylase activity (65-74%). A dose-dependent protection against these METH-induced decreases was seen with two noncompetitive NMDA antagonists, ifenprodil and SL 82.0715 (25-50 mg/kg/injection), both of which are thought to bind to a polyamine or sigma site associated with the NMDA receptor complex, and with two competitive NMDA antagonists, CGS 19755 (25-50 mg/kg/injection) and NPC 12626 (150-300 mg/kg/injection). Moreover, an intrastriatal infusion of NMDA (0.1 mumol) produced a slight but significant loss of neostriatal dopamine which was potentiated in mice that also received a systemic injection of METH. The results of these studies strengthen the hypothesis that the excitatory amino acids play a critical role in the nigrostriatal dopaminergic damage induced by METH.     

Lobeline attenuates methamphetamine-induced changes in vesicular monoamine transporter 2 immunoreactivity and monoamine depletions in the striatum

L-Lobeline is an alkaloid that inhibits the behavioral effects of methamphetamine (METH) in rats. No studies have examined the effects of lobeline on the acute and long-term neurochemical changes produced by neurotoxic doses of METH. The effects of lobeline on METH-induced dopamine release, alterations in vesicular monoamine transporter 2 (VMAT-2) distribution, and long-term depletions of dopamine and serotonin (5-HT) content in the rat striatum were examined. METH increased body temperature and dopamine release, decreased VMAT-2 immunoreactivity at 1 and 24 h after METH, and decreased dopamine and 5-hydroxytryptamine (5-HT) content in striatum when examined 7 days later. Prevention of METH-induced hyperthermia attenuated the decrease in VMAT-2 as well as dopamine and 5-HT content. Lobeline pretreatment did not affect METH-induced dopamine release but attenuated the decreases in VMAT-2 after METH and the long-term decreases in striatal dopamine and 5-HT content. These effects of lobeline were due partly to the attenuation of METH-induced hyperthermia. The maintenance of hyperthermia during lobeline + METH exposure restored the effects of METH on decreases in VMAT-2 as well as dopamine and 5-HT content. To examine the effects of lobeline independent of its effects on METH-induced hyperthermia, lobeline was administered after METH when body temperature returned to normal. Lobeline treatment at 5 and 7 h after METH attenuated the METH-induced decreases in synaptosomal, membrane-associated, and vesicular VMAT-2 24 h after METH, as well as the METH-induced decreases in dopamine and 5-HT content 7 days later. Therefore, lobeline has both temperature-dependent and -independent neuroprotective effects against METH toxicity.     

局部麻醉剂通过丝裂原活化蛋白激酶途径诱导人甲状腺癌细胞凋亡

目的探讨局部麻醉剂对人甲状腺癌细胞凋亡的影响及其作用机制。方法MTT法检测人甲状腺癌细胞经0 mM、1 mM、2 mM、4 mM、8 mM和16 mM的利多卡因及0 mM、0.2 mM、0.4 mM、0.8 mM、1.6 mM和3.2 mM的布比卡因分别干预24 h和48 h后的细胞活力流式细胞仪检测经4 mM和8 mM的利多卡因和0.8 mM和1.6 mM的布比卡因干预48 h后癌细胞的凋亡及线粒体膜电位;Western Blot检测凋亡相关因子及丝裂原活化蛋白激酶(MAPK)途径相关蛋白的表达;分别采用SP600125(JNK抑制剂)、PD98059(MEK抑制剂)、SB203580(p38 MAPK抑制剂)联合利多卡因或布比卡因对细胞进行处理,Western Blot检测凋亡相关蛋白的表达。结果利多卡因和布比卡因干预24 h和48 h均可呈剂量依赖式抑制人甲状腺癌细胞的生长。利多卡因和布比卡因干预48 h可降低癌细胞线粒体膜电位,增加Caspase-3和Bax的表达,降低Bcl-2的表达激活p38和JNK,抑制ERK的活性。MAPK信号通路抑制剂可降低利多卡因和布比卡因诱导Caspase-3和Bax的表达,增加Bcl-2的表达。结论局部麻醉剂利多卡因和布比卡因可诱导人甲状腺癌细胞生存抑制和凋亡,其机制与MAPK通路激活有关。     

Manganese superoxide dismutase and inducible nitric oxide synthase modify early oxidative events in acute adriamycin-induced mitochondrial toxicity

In the present study, we used genetically engineered B6C3 mice [mice overexpressing manganese superoxide dismutase (TgM(+/+)), mice in which inducible nitric oxide synthase had been inactivated (iNOSKO(-/-)), and crosses of these two genotypes] to study the role of manganese superoxide dismutase (MnSOD) and inducible nitric oxide synthase (iNOS) in the development of acute Adriamycin-induced cardiotoxicity. Both nontransgenic and genetically engineered mice were treated with 20 mg/kg Adriamycin and cardiac left ventricular tissues studied at 0, 3, 6, and 24 hours. Ultrastructural damage and levels of 4-hydroxy-2-nonenal (4HNE) protein adducts and 3-nitrotyrosine (3NT) were determined in cardiomyocytes using immunogold ultrastructural techniques. Our previous results showed that Adriamycin caused mitochondrial injury without significant nuclear or cytoplasmic damage at early time points. Interestingly, overexpression of MnSOD protected against acute mitochondrial injury, whereas deficiency in iNOS potentiated mitochondrial injury in comparison with levels of injury present in cardiomyocyte mitochondria of nontransgenic mice. In TgM(+/+) mice, there was a significant inverse correlation between mitochondrial injury and 4HNE/3NT levels at all time points analyzed, suggesting that reactive oxygen species/reactive nitrogen species damage products directly regulated acute Adriamycin-induced mitochondrial injury in these mice. The present studies are the first to directly quantify the effects of MnSOD and iNOS on mitochondrial injury during acute Adriamycin-induced cardiotoxicity and show extensive and specific patterns of posttranslational modifications of mitochondrial proteins following Adriamycin treatment.     

Methamphetamine-induced rapid decrease in dopamine transporter function: role of dopamine and hyperthermia

Single and multiple high-dose administrations of methamphetamine (METH) differentially decrease dopamine (DA) transporter (DAT) function, as assessed by measuring [(3)H]DA uptake into rat striatal synaptosomes prepared 1 h after treatment. Prevention of METH-induced hyperthermia attenuated the decrease in DAT activity induced by multiple injections of the stimulant. Likewise, this decrease was attenuated by previous depletion of striatal DA levels using alpha-methyl-p-tyrosine (alphaMT) or pretreatment with the D1 and D2 antagonists SCH-23390 and eticlopride, respectively. However, METH-induced hyperthermia was also blocked by alphaMT and eticlopride. Reinstatement of hyperthermia to alphaMT- or eticlopride-pretreated rats partially restored the METH-induced decrease in DAT activity. In contrast, neither prevention of METH-induced hyperthermia depletion of DA, nor DA antagonists altered the decrease in DAT function induced by a single administration of METH. Pretreatment with the antioxidant N-t-butyl-alpha-phenylnitrone prevented part of the decrease in DAT function associated with multiple, but not a single, METH injections. Although not tested directly, additional data presented here suggest that the reduction in DAT activity induced by a single METH administration constitutes a part of the total reduction observed immediately after multiple administrations. Taken together, the results indicate that DA, hyperthermia, and oxygen radicals contribute to a component of the rapid decrease in DAT function induced by multiple injections of METH but do not appear to be associated with the reduction induced by a single administration of the stimulant.     

A new signaling mechanism of hepatocyte growth factor-induced endothelial proliferation

BACKGROUND: The hepatocyte growth factor (HGF) has been shown to promote endothelial cell proliferation. In this study, the signaling cascade responsible for the HGF-induced proliferation was examined. METHODS: The proliferation of human umbilical cord vein endothelial cells (HUCVEC) was determined using cell counts. Changes of the membrane potential were analyzed using the fluorescence dye DiBAC. Intracellular cGMP-levels were measured by means of [3H]-cGMP-radioimmunoassay. Phosphorylation of the p42/p44 MAP-kinase (MAPK) and the endothelial nitric oxide synthase (eNOS) was analyzed by immunocytochemistry. RESULTS: A dose-dependent (1-30 ng mL(-1)) increase of HUCVEC proliferation with a maximum at a concentration of 15 ng mL(-1) was induced by HGF. This effect was significantly reduced by the addition of the K+ channel blocker iberiotoxin (100 nmol L(-1)), eNOS inhibitor L-NMMA (300 micromol L(-1)), or the MEK inhibitor PD 98059 (20 micromol L(-1)). A HGF-induced hyperpolarization that was blocked by iberiotoxin was observed. In addition, HGF-induced activation of the eNOS was blocked by the K+ channel inhibitor. An increase of +101% MAPK phosphorylation was induced by HGF, which was blocked, if the cells were treated with L-NMMA (n = 20; P < 0.05), whereas HGF-induced phosphorylation of the eNOS was not affected by MEK inhibition. CONCLUSIONS: Hepatocyte growth factor modulates endothelial K+ channels causing an activation of the eNOS; the increase of nitric oxide is necessary for the phosphorylation of the MAPK inducing the proliferation of HUCVEC.