N-乙酰半胱氨酸对毒胡萝卜素诱导的HepG2细胞内质网氧化应激凋亡的影响

目的 了解N-乙酰半胱氨酸(NAC)对内质网氧化应激介导的肝细胞凋亡的阻抑作用.探讨其治疗肝细胞损伤的作用机制.方法 用毒胡萝卜素(TC)诱导HepG2细胞,建立内质网应激凋亡模型,用NAC进行干预.噻唑蓝(MTT)、流式细胞仪、DNA梯形电泳检测凋亡率及活性氧(ROS),Western印迹检测葡萄糖调节蛋白(GRP)78、Caspase-12酶原及ADP聚合酶(PARP)表达.多样本间均数采用方差分析.结果 用2μmol/L TG诱导HepG2细胞0、24、36和48 h,随诱导时间延长,细胞活力逐渐下降;GRP 78、Caspase-12酶原及PARP表达增高;凋亡率逐渐增加.分别是0.7%±0.5%、27.6%±6.3%、29.7%±3.03%和47.9%±3.5%(P<0.05);ROS产生逐渐增加,分别是14.0%±0.5%、36.1%±300%、38.2%±6.0%和48.3%±12.4%(P<0.05);诱导36、48 h后细胞出现典型DNA梯形条带.10 mmol/L、20 mmol/L NAC分别与2/μmol/L TG共同温育HepG2细胞后发现,NAC可明显提高细胞活力;抑制GRP 78、Caspase-12酶原及PARP表达,细胞凋亡率分别降至14.0%±1.3%和11.0%±0.3%;细胞内ROS的产生减至34.7%±0.8%与31.5%±2.9%.结论 TG作为一种内质网特异的钙离子ATP酶抑制剂,能触发HepG2细胞内质网氧化应激凋亡;而NAC作为巯基合成的前体.直接抑制氧自由基反应,阻断内质网氧化应激介导的细胞凋亡,减轻肝细胞损伤,达到临床治疗肝功能衰竭的作用.     

胡黄连苷Ⅱ对H2O2损伤L-02细胞的保护作用

目的:探讨胡黄连苷Ⅱ(picroside Ⅱ)对氧化应激损伤L-02细胞的保护作用.方法:H2O2损伤的L-02细胞作为氧化应激损伤模型,MTT法检测细胞增殖状况,膜联蛋白(Annexin-Ⅴ)和碘化丙啶(PI)染色流式细胞术(flow cytometry,FCM)检测细胞凋亡,罗丹明123染色FCM检测细胞线粒体膜电位(mitochondrial potential membrane,△Ψm),双氢罗丹明123染色FCM检测细胞内活性氧(reactive oxygen species,ROS)的含量.结果:0.6 mmol/L H2O2可诱导L-02细胞凋亡.细胞内ROS浓度增加,细胞线粒体跨膜电位明显下降.预先经过0.05,0.5,5 mmol/L浓度的胡黄连苷Ⅱ处理后,H2O2诱导的L-02细胞凋亡明显减少(30.8%±9.09%,10.2%±9.82%,8.2%±7.10%vs 42.8%±8.28%,均P＜0.01),同时明显减弱H2O2对细胞内ROS浓度和线粒体跨膜电位的影响.结论:胡黄连苷Ⅱ对氧化应激损伤L-02细胞具有保护作用,其机制可能与降低细胞内ROS含量,进而抑制△Ψm的降低有关.     

花青素抗氧化损伤及细胞凋亡的作用研究

目的:探索花青素对H2O2引起的Huh7细胞氧化应激、细胞凋亡的作用及其机制.方法:对H2O2和花青素干预培养的Huh7细胞,应用MTT法检测细胞活力,荧光探针DCFH-DA测定细胞内活性氧(ROS)生成量,免疫印迹测定Akt、磷酸化激活的c-Jun蛋白水平.结果:H2O2 0.8mmol/L孵育1小时可显著诱导Huh7细胞损伤,细胞活力下降到(49.27±3.2)%,ROS生成量是未处理细胞的3.56倍.细胞经花青素50μmol/L与H2O2共孵育后,细胞存活率提高到(81.2±2.34)%;花青素能显著抑制H2O2引起的Huh7细胞ROS生成,ROS生成下降74%(P＜0.01).花青素抑制H2O2引起Huh7细胞死亡和ROS生成的效应随剂量增加而加强.花青素抑制H2O2激发Huh7细胞磷酸化c-Jun表达,提高细胞Akt水平.结论:花青素抑制H2O2引起的Huh7细胞氧化应激损伤所导致的细胞死亡,其作用机制在于减少细胞内活性氧生成,抑制H2O2激活磷酸化c-Jun,提高细胞Akt水平.     

VEGF在二甲双胍诱导HepG2细胞凋亡的作用

目的初步探讨二甲双胍(metformin,MET)诱导人肝癌HepG2细胞凋亡的分子机制.方法将不同浓度的MET(0-20 mmol/L)作用于HepG2细胞24 h或10 mmol/LMET作用于HepG2细胞不同时间(0-48 h),采用MTT法测定MET抑制细胞增殖效应.将HepG2细胞暴露于不同浓度的MET(0-20 mmol/L)作用24 h或10 mmol/L MET不同时间(0-48 h),用Annexin V-FITC/PI流式双染来测定其细胞凋亡率;用RT-PCR检测不同浓度MET作用于HepG2细胞或相同浓度作用于HepG2细胞不同时间后血管内皮生长因子(vascular endothelial growth factor,VEGF)表达的变化,以了解MET诱导HepG2细胞凋亡与VEGF的关系.结果MET对HepG2细胞生长有明显的抑制作用.不同浓度MET(0、5、10、15、20 mmol/L)处理HepG2细胞24 h后,其相对细胞活力分别为100%、80.56%±0.72%、71.06%±0.70%、64.73%±0.35%、54.73%±0.40%,呈现浓度依赖性;10 mmol/L MET作用于HepG2细胞0、12、24、36、48 h后,其相对相对细胞活力分别为100%、83.40%±0.70%、69.86%±0.45%、60.40%±0.88%、50.70%±0.45%,呈现时间依赖性.不同浓度MET(0、5、10、15、20 mmol/L)处理HepG2细胞24 h后,Annexin V-FITC/PI流式双染提示细胞凋亡明显增加,其凋亡率分别为2.78%±0.68%、9.33%±0.22%、17.13%±0.10%、21.61%±0.20%、25.26%±1.09%,呈现浓度依赖性;10 mmol/LMET作用于HepG2细胞12、24、36、48 h后,Annexin V-FITC/PI流式双染提示细胞凋亡明显增加,其凋亡率分别为2.05%±0.04%、8.10%±0.08%、16.53%±0.93%、20.95%±0.16%、25.65%±0.44%,呈现时间依赖性.随着MET浓度的升高或作用时间延长,VEGF的表达均减少,呈现剂量或时间依赖性.结论二甲双胍可以通过诱导HepG2细胞凋亡来抑制其增殖,其过程可能与抑制VEGF的表达有关.     

JNK/SAPK信号转导系统在三氧化二砷诱导肝癌细胞凋亡中的作用

目的:探讨JNK/SAPK信号转导系统在三氧化二砷(As2O3)诱导人肝癌细胞株HepG2凋亡过程中的作用.方法:采用MTT法观察不同浓度的As2O3对人类肝癌细胞株HepG2细胞生长的抑制作用;以流式细胞术观察细胞的凋亡率及生长周期的变化;以Western blot法检测p-MEK4、JNK、P-JNK、Caspase-3及PARP蛋白在As2O3作用下及SP600125阻断JNK信号转导通路情况下的表达.结果:各浓度As2O3均能明显抑制肝癌细胞HepG,增殖,且具有剂量依赖性和时间依赖性;流式细胞术(FCM)分析显示,As2O3能够诱导肝癌细胞HepG2凋亡且具有时间依赖性,细胞滞留于G2/M期(0,24,48,72 h百分率分别为7.22%±1.50%,11.56%±0.73%,33.8%±1.62%,46.02%±0.11%):Western blotting结果显示,As2O3诱导肝癌细胞HepG2凋亡伴随着Caspase-3和PARP的活化;As2O3作用于HepG2细胞10 min后P-MEK4和P-JNK蛋白表达开始增加,20 min达到高峰,30 min开始减少,总JNK蛋白的含量无明显改变,MEK4和JNK的激活早于细胞凋亡;用SP600125预处理HepG2细胞株后,可以明显减少Caspase-3和PARP的活化.结论:As2O3可以体外通过诱导细胞凋亡抑制肝癌细胞株HepG2的增殖,细胞凋亡通过Caspase-3途径实现.JNK信号转导通路参与了As2O3诱导的HepG2凋亡反应,并位于Caspase-3的上游.     

活性氧在亚砷酸钠诱导Chang肝细胞凋亡中的作用

目的研究在亚砷酸钠（NaAsO2）诱导人Chang肝细胞株的凋亡过程中细胞内活性氧（ROS）和还原型谷胱甘肽（GSH）的作用。方法通过流式细胞术Annexin V/PI双染法检测细胞凋亡,采用2′,7′-二乙酰二氯荧光素（DCFH-DA）检测细胞内ROS水平,应用DTNB法测定细胞内GSH含量。结果与对照组相比,在5～30μmol/LNaAsO2浓度范围内,随着NaAsO2浓度的增高,Chang肝细胞凋亡率、细胞内ROS水平及GSH含量均升高（P〈0.05） 5mmol/L N-乙酰半胱氨酸（NAC）可显著抑制NaAsO2诱导的细胞凋亡的发生（P〈0.05）及细胞内ROS水平的升高（P〈0.05）,但细胞内GSH含量继续升高（P〈0.05）。结论砷诱导的Chang肝细胞的凋亡可能主要取决于细胞内ROS的产生,而不是细胞内GSH含量的下降。     

白藜芦醇对酒精诱导的HepG2细胞氧化损伤的保护作用及相关基因表达的变化

目的:探讨白藜芦醇在酒精诱导的HepG2细胞氧化应激中的抗氧化作用,揭示白藜芦醇抗酒精性肝损伤的作用机制.方法:白藜芦醇预处理HepG2细胞24 h后,用酒精诱导氧化应激的产生.MTT方法检测白藜芦醇处理组与对照组HepG2细胞活力;用ELISA试剂盒检测不同实验组的超氧化物歧化酶(superoxide dismutase,SOD)和细胞内总活性氧(reactive oxygen species,ROS)含量;采用RTPCR方法检测抗氧化通路中关键基因SOD1、SOD2和过氧化氢酶的mRNA表达水平.结果:MTT结果显示,与对照组比较,白藜芦醇(12.5、25、50、100μmol/L)对HepG2细胞的细胞毒性均在20%以下,300 mmol/L酒精可致近50%HepG2细胞死亡;25-100μmol/L白藜芦醇可有效对抗300 mmol/L酒精对HepG2引起的细胞毒性作用;SOD活性显示100μmol/L白藜芦醇预处理组SOD含量(0.391±0.011)明显高于非处理组(0.286±0.019),而ROS结果显示酒精诱导组(29234.79±2288)明显高于白藜芦醇25、50、100μmol/L预处理组(18023.26±1359.66;13528.44±1078.99;8219.87±635.99);RT-PCR结果显示,与300mmol/L酒精比较,25、50和100μmol/L白藜芦醇可上调SOD1 mRNA表达量(0.5535±0.0035;0.586±0.0113;0.623±0.0127);12.5、25、50、100μmol/L白藜芦醇均可上调SOD2mRNA表达量(1.249±0.011;1.369±0.028;1.377±0.021;1.401±0.0578);50和100μmol/L白藜芦醇均可上调过氧化氢酶(0.1955±0.004;0.2275±0.00707)mRNA的表达量.结论:本研究提示酒精可诱导氧化应激的产生,而白藜芦醇通过调节抗氧化通路中基因的表达发挥抗氧化功能,从而削弱酒精的细胞损伤作用.     

外源性NO诱导胃癌SGC-7901细胞凋亡的作用机制

目的:探讨外源性一氧化氮(nitric oxide,NO)诱导中分化胃癌细胞株(SGC-7901)凋亡的潜在机制.方法:采用不同浓度的外源性NO供体硝普钠(sodium nitroprusside,SNP)处理细胞,M T T法检测细胞的存活率;荧光显微镜检测细胞的凋亡形态及凋亡率.依据有无活性氧(reactive oxygen species,ROS)抑制剂N-乙酰半胱氨酸(N-acetyl-L-cysteine,NAC)和SNP作用细胞,实验分4组:对照组、NAC组、SNP组、NAC+SNP组.采用荧光化学发光仪检测胞内ROS水平;流式细胞仪检测细胞的凋亡;Western blot检测铜锌超氧化物歧化酶(Cu/Zn-superoxide dismutase,Cu/ZnS O D)蛋白的表达.所有数据采用S P S S17.0分析.结果:(1)SNP可诱导胃癌细胞凋亡,且有浓度及时间依赖性;(2)NAC组和对照组在细胞凋亡率及胞内ROS水平上差异无统计学意义(P0.05);(3)较对照组,单独SNP可使细胞凋亡率及胞内ROS水平明显升高(P0.05);而经NAC干预后,SNP引起的细胞凋亡率和胞内ROS水平均下降(P0.05),但仍高于对照组;(4)SNP可引起细胞Cu/Zn-SOD蛋白表达的降低.结论:外源性NO可通过抑制胃癌细胞Cu/ZnSOD蛋白的表达而上调其ROS水平,该功能可能参与其诱导的胃癌细胞凋亡途径.     

三七总皂苷减轻过氧化氢诱发的对肾小管上皮细胞的氧化应激损害

目的观察三七总皂苷(PNS)对过氧化氢(H2O2)诱导人肾小管上皮细胞(HK-2)的氧化应激损害的保护作用及其机制。方法培养HK-2并分组:正常组(不加任何干预因素), H2O2组(在细胞培养体系中加入终浓度为400 μmol/L的H2O2, 培养6 h)和PNS组(分为3组:先在细胞培养体系中分别加入PNS 25 μg/ml、50 μg/ml和100 μg/ml, 培养4 h, 再加入终浓度为400 μmol/L的H2O2, 继续培养6 h), 观察H2O2刺激HK-2发生凋亡情况。结果与正常组相比, H2O2组细胞存活率降低为(45.67±2.52)%、细胞凋亡率升高至(19.23±1.63)%(均P<0.01), 而PNS组各组的细胞存活率分别为(55.12±2.33)%、(65.37±4.72)%和(83.46±1.52)%, 细胞凋亡率分别降低至(15.53±0.70)%、(12.53±1.30)%和(7.17±0.35)%, 50 μg/ml和100 μg/ml PNS组的HK-2细胞内活性氧(ROS)水平分别为(845.7±17.79)和(353.3±26.1);3...     

氯通道ClC-3反义寡核苷酸对过氧化氢诱导的大鼠主动脉平滑肌细胞凋亡的影响

目的研究ClC3反义寡核苷酸对H2O2诱导的大鼠主动脉平滑肌细胞凋亡的影响。方法蛋白免疫印迹法检测ClC3蛋白表达;形态学方法、DNA琼脂糖电泳、MTT法和流式细胞仪观察和分析H2O2诱导的大鼠主动脉平滑肌细胞形态学改变、DNA断裂、细胞存活率和凋亡率及ClC3反义寡核苷酸转染对其影响。结果ClC3反义寡核苷酸转染抑制内源性ClC3蛋白表达后,可加重H2O2诱导大鼠主动脉平滑肌细胞形态学改变及DNA断裂,细胞凋亡率由52.8%±13.6%增至75.7%±5.8%(n=6,P<0.01),而细胞存活率由48.9%±4.3%进一步降低为31.3%±4.3%(n=6,P<0.01)。结论ClC3反义寡核苷酸转染促进H2O2诱导的大鼠主动脉平滑肌细胞凋亡。     

The sensitivity of digestive tract tumor cells to As2O3 is associated with the inherent cellular level of reactive oxygen species

AIM: To explore the correlation of the inherent cellular ROS level with the susceptibility of the digestive tract tumor cells to apoptosis inducted by As2O3. METHODS: Two gastric carcinoma cell lines, SGC7901 and MKN45, and two esophageal carcinoma cell lines, EC/CUHK1(alternatively named EC1.71) and EC1867 with low concentration(2 micromol x L(-1))of As2O3 were cultured espectly, which confirmed the difference in apoptosis susceptibility between SGC7901 and MKN45, and between EC/CUHK1 and EC1867. The cells were incubated with dihydrogenrhodamine123 (DHR123), used as a ROS capture in absence of As2O3.The fluorescent intensity of rhodamine123, which was the product of cellular oxidation of DHR123, was detected by flow cytometry, and ROS was measured. RESULTS: Apoptosis induced by a low concentration of As2O3 was more readily to occur in SGC7901(22.4%+/-2.4%) and EC/CUHK1(27.0%+/-2.9%) than in MKN45(2.1%+/-0.5%) and EC1867(0.8%+/-0.5%).In other words, SGC7901 was more sensitive than MKN45 to As2O3, meanwhile EC/CUHK1 was more sensitive than EC1867 to As2O3. The level of inherent cellular ROS in SGC7901(650+/-37) was higher than that in MKN45(507+/-22)(P<0.01), and the level of inherent cellular ROS in EC/CUHK1(462+/-17) was higher than that in EC1867(187+/-12)(P<0.01).CONCLUSIONS: The cellular sensitivity to apoptosis induced by As2O3 is associated with the difference in cellular ROS level. The inherent ROS level might determinate the apoptotic sensitivity of tumor cells to As2O3.     

重组人生长激素对内毒素致肝细胞凋亡效应的抑制作用

目的观察内毒素（LPS）对肝细胞的直接作用及重组人生长激素（rhGH）的干预效果。方法内毒素诱导肝细胞损害,HepG2细胞传代培养24h后,换用含内毒素（20μg/ml）和/或rhGH、肝细胞生长因子（HGF）的新鲜培养液继续培养16h,观察药物对LPS作用的干预效果。结果HepG2细胞经LPS作用16h,透射电镜观察既有形态正常的细胞,同时也出现典型的凋亡细胞表现为胞浆浓缩核凝聚成块状,凋亡小体形成,细胞器（包括线粒体）结构基本正常;TUNEL标记后胞核呈棕褐色染色,而对照细胞无阳性染色信号,证实LPS作用16h后HepG2细胞已发生凋亡。将rhGH与LPS同时加入培养液中共同作用16h,rhGH可明显减少HepG2细胞经LPS诱导的细胞凋亡数量对照组为（99±0.8）%,rhHG处理组为（36±5.6）%,P＜0.001。结论重组人生长激素可以抑制LPS致肝细胞凋亡作用。     

N-acetyl cysteine inhibits human signet ring cell gastric cancer cell line (SJ-89) cell growth by inducing apoptosis and DNA synthesis arrest

BACKGROUND AND AIMS: In this study, we investigated the inhibitory effects of N-acetyl cysteine (NAC) on the growth of the human signet ring cell from the gastric-cancer cell line SJ-89 , via the induction of apoptosis and the arrest of DNA synthesis. MATERIALS AND METHODS: SJ-89 cells were regularly incubated in the presence of NAC at 5, 10 and 20 mmol/l, and with IMDM as untreated control. Trypan blue-dye exclusion analysis and 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide assay were applied to detect cell proliferation. Apoptotic morphology was observed by electron microscopy. Flow cytometry and terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling (TUNEL) assay were performed to detect NAC-triggered apoptosis. RESULTS: NAC could inhibit proliferation of human gastric cancer SJ-89 cells in a dose-dependent and time-dependent manner. The growth curve showed suppression by 15.8, 37.6 and 66.3% following 72 h of NAC treatment at 5, 10 and 20 mmol/l, respectively, similar to the findings of 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide assay. DNA synthesis was evidently reduced by 25, 39 and 91% after 24 h NAC treated at 20 mmol/l and 5 days at 10 and 20 mmol/l, respectively. Cell growth was inhibited by 100% with the treatment of 20 mmol/l NAC on day 6. NAC-treated SJ-89 cells were characterized by typical apoptotic alterations, including morphological changes by electron microscopy, typical apoptotic sub-G1 peaking observed by flow cytometry and increase of apoptotic cells with the elevation of the concentration of NAC in a clearly dose-dependent manner by TUNEL assay. Electrophoresis analysis showed typical 'DNA ladder'. CONCLUSION: The data above implicated that NAC inhibits human gastric-cancer SJ-89 cell growth by inducing apoptosis and DNA synthesis arrest. Although the exact mechanisms involved in NAC-induced apoptosis have not been known up to now, the ability to induce apoptosis in a tumor-cell population within 48 h is worth noting. It is also noteworthy that NAC can selectively inhibit the growth of tumor cells. Further studies are needed to elucidate the mechanisms.     

N-acetylcysteine attenuates reactive-oxygen-species-mediated endoplasmic reticulum stress during liver ischemia-reperfusion injury

AIM: To investigate the effects of N-acetylcysteine (NAC) on endoplasmic reticulum (ER) stress and tissue injury during liver ischemia reperfusion injury (IRI).METHODS: Mice were injected with NAC (300 mg/kg) intraperitoneally 2 h before ischemia. Real-time polymerase chain reaction and western blotting determined ER stress molecules (GRP78, ATF4 and CHOP). To analyze the role of NAC in reactive oxygen species (ROS)-mediated ER stress and apoptosis, lactate dehydrogenase (LDH) was examined in cultured hepatocytes treated by H₂O₂ or thapsigargin (TG).RESULTS: NAC treatment significantly reduced the level of ROS and attenuated ROS-induced liver injury after IRI, based on glutathione, malondialdehyde, serum alanine aminotransferase levels, and histopathology. ROS-mediated ER stress was significantly inhibited in NAC-treated mice. In addition, NAC treatment significantly reduced caspase-3 activity and apoptosis after reperfusion, which correlated with the protein expression of Bcl-2 and Bcl-xl. Similarly, NAC treatment significantly inhibited LDH release from hepatocytes treated by H₂O₂ or TG.CONCLUSION: This study provides new evidence for the protective effects of NAC treatment on hepatocytes during IRI. Through inhibition of ROS-mediated ER stress, NAC may be critical to inhibit the ER-stress-related apoptosis pathway.     

Apoptosis in human aortic endothelial cells induced by hyperglycemic condition involves mitochondrial depolarization and is prevented by N-acetyl-L-cysteine

We investigated whether the dissipation of mitochondrial transmembrane potential (Delta(Psi)(m)) was involved in apoptosis of cultured human aortic endothelial cells (HAECs) exposed to hyperglycemic conditions (30 mmol/L glucose). In parallel experiments, N-acetyl-L-cysteine (NAC) was added to the culture medium to verify whether this antioxidant may prevent apoptosis in these cells. The binding of annexin V and DNA fragmentation were measured, in addition to the production of reactive oxygen species (ROS), the number of cells with depolarized mitochondria, and the intracellular glutathione (GSH) content. As compared to the control (5 mmol/L glucose), high-glucose treatment increases both ROS generation and the number of cells binding annexin V. Moreover, a simultaneous decrease of intracellular GSH content was observed, which was accompanied by an increased number of cells showing both depolarized mitochondria and fragmented DNA. Incubation of HAECs with high glucose in the presence of 10 mmol/L NAC prevented the drop of intracellular GSH content, and decreased both ROS generation and the number of cells committed to apoptosis. These results suggest that high glucose triggers the same cascade of molecular events as do other apoptosis inducers in other cells. Among these events, the disruption of mitochondrial membrane barrier function might be decisive because it causes the release of soluble proteins from intermembrane space, which then induce nuclear apoptotic changes.     

N-乙酰半胱氨酸通过抑制活性氧-p38通路减轻缺氧复氧诱导的乳鼠心肌细胞凋亡

目的 探讨N-乙酰半胱氨酸(N-acetylcysteine,NAC)抑制缺氧复氧(hypoxia-reoxygenation,H/R)诱导的乳鼠心肌细胞凋亡的机制.方法 心肌细胞培养48 h后随机分为对照组、缺氧复氧组(H/R组)、缺氧复氧+NAC组(100 p.mol/L)(H/R+NAC组).H/R组心肌细胞先缺氧6 h,随后复氧72 h,H/R+NAC组在H/R组细胞培养液中加NAC(100 μmol/L).采用锥虫蓝检测心肌细胞活性.流式细胞仪与Annexin V测定细胞早期凋亡.TUNEL检测细胞晚期凋亡.活性氧绿色荧光显色试剂检测活性氧(reactive oxygen species,ROS)浓度.RT-PCR检测bcl2、bax基因mRNA水平.Western blot检测bel2、bax、p38与pp38基因蛋白水平.结果 H/R组有活性的细胞数量为74.9%,显著低于对照组(93.5%,P<0.01),H/R+NAC组有活性的细胞数为89.9%,显著高于H/R组(P<0.01).H/R组早期凋亡的心肌细胞数为25.2%,显著高于对照组(6.5%,P<0.01),H/R+NAC组早期凋亡的细胞数为11.1%,显著低于H/R组(P<0.01).H/R组晚期凋亡的心肌细胞数为33.5%,显著高于对照组(3.5%,P<0.01),H/R+NAC组晚期凋亡的细胞数为13.5%,显著低于H/R组(P<0.01).H/R组心肌细胞ROS产生显著高于对照组,H/R+NAC组心肌细胞ROS产生显著低于H/R组.H/R组pp38/p38条带密度比值(13.40)也显著高于对照组(3.89).H/R+NAC组pp38/p38条带密度比值(1.95)显著低于H/R组(13.4),P<0.01.H/R组bcl2 mRNA与蛋白水平显著低于对照组,bax mRNA与蛋白水平显著高于对照组.H/R+NAC组bcl2 mRNA与蛋白水平显著高于H/R组.H/R+NAC组bcl2/bax mRNA水平比值(1.79)显著高于H/R组(1.22),P<0.05,但仍低于对照组(1.85).H/R+NAC组bcl2/bax条带密度比值(0.71)显著高于H/R组(0.50),P<0.05,但仍低于对照组(2.53).结论 NAC通过抑制ROS-p38通路减轻缺氧复氧诱导的乳鼠心肌细胞凋亡,这一作用具有潜在的临床应用价值.     

阿托伐他汀减轻巨噬细胞内质网应激及其介导的细胞凋亡

目的 探讨阿托伐他汀对7-酮胆固醇（7-KC）诱导的巨噬细胞内质网应激及细胞凋亡的影响。方法 AopE-/-小鼠左肾动脉和左颈总动脉联合部分结扎建立颈动脉易损斑块模型。采用HE染色方法观察斑块病理学改变,用免疫荧光结合激光扫描共聚焦显微镜技术检测斑块中内质网应激(ER stress)相关蛋白CHOP及磷酸化PERK（p-PERK）的表达。体外培养小鼠巨噬细胞RAW264.7,给予7-KC、H2O2或联合阿托伐他汀处理后,蛋白质免疫印迹方法（Western blot）测定ER stress相关蛋白CHOP、p-PERK 、XBP-1s及凋亡相关蛋白cleaved caspase-3的表达。结果 AopE-/-小鼠颈动脉易损斑块局部ER stress相关蛋白CHOP的表达及PERK磷酸化水平明显上调;7-KC可诱导小鼠巨噬细胞ER stress,进而诱导细胞凋亡;同时,氧化应激诱导剂H2O2也可通过诱导小鼠巨噬细胞ER stress介导细胞凋亡;而阿托伐他汀可抑制7-KC和H2O2诱导的巨噬细胞ER stress及其介导的细胞凋亡。结论 ER stress可能参与AS易损斑块的形成;阿托伐他汀可通过减少细胞内氧化应激的水平,减轻巨噬细胞ER stress,从而抑制细胞凋亡。     

Hexarelin对H2O2诱导的大鼠胸主动脉内皮细胞损伤的抑制作用及其机制

目的：观察人工合成的生长激素释放肽hexarelin对H2O2诱导的大鼠胸主动脉内皮细胞损伤是否有抑制作用及可能的机制。方法：体外原代培养的大鼠胸主动脉内皮细胞,随机分为对照组、H2O2组及H2O2＋10-5 mmol/Lhexarelin组和H2O2＋10-7 mmol/L hexarelin组,通过光镜和电镜观察各组细胞的形态学变化。采用MTT比色法检测各组细胞活力的变化;用比色法检测内皮细胞培养上清液中乳酸脱氢酶（LDH）的含量;用硝酸还原酶法检测内皮细胞培养上清液中一氧化氮（NO）的含量。结果：光镜和电镜观察发现,H2O2可以诱导大鼠胸主动脉内皮细胞损伤及凋亡;而Hexarelin能减轻H2O2所诱导的内皮细胞损伤及凋亡。MTT比色法检测发现,H2O2能使内皮细胞的活力由（0.39±0.03）下降为（0.23±0.04）（P〈0.01）;而1×10-5和1×10-7 mmol/L hexarelin能减轻H2O2对内皮细胞活力的影响,内皮细胞的活力分别由（0.23±0.04）变为（0.30±0.02）和（0.29±0.02）（P〈0.01）。H2O2能诱导内皮细胞产生LDH,由（31.11±4.97）U/L上升为（157.48±7.33）U/L（P〈0.01）;而1×10-5和1×10-7mmol/L hexarelin能减少LDH的生成,由[（157.48±7.33）U/L下降为（55.12±6.11）U/L和（94.48±4.07）U/L（P〈0.01）。另外,H2O2能引起NO生成减少,由（29.38±6.14）μmol/L降为（17.24±7.51）μmol/L（P〈0.01）,而hexarelin能逆转H2O2引起的内皮细胞NO生成的减少,由（17.24±7.51）μmol/L变为（35.95±4.89）μmol/L和（19.73±2.50）μmol/L（P〈0.01）。结论：Hexarelin能够抑制H2O2所诱导的大鼠胸主动脉内皮细胞的损伤及其凋亡,其机制可能与hexarelin抑制氧化应激反应及促进NO的产生有关。