氧化应激诱导HepG2肝癌细胞凋亡的研究(英)

目的：直接暴露细胞于活性氧能诱导发生凋亡，本文研究氧化应激诱导HepG2肝癌细胞的死亡及其机制。方法：暴露细胞于2 mmol/L过氧化氢产生氧化应激，用DNA凝胶电泳检测细胞凋亡，用荧光染色法检测细胞线粒体膜电位变化，Western blotting检测细胞浆中细胞色素c变化，fluorometric assay kit检测caspase活性变化。结果：氧化应激作用于HepG2细胞后12 h开始发生凋亡；氧化应激作用后4 h，细胞线粒体膜电位明显下降；胞浆中细胞色素c浓度呈时间依赖性增高；氧化应激作用8 h、12 h后细胞内caspase-3、caspase-9活性分别升高6.7及3.6倍，但caspase-8活性无变化。结论：氧化应激能诱导HepG2肝癌细胞发生凋亡，其途径与线粒体通路及caspase激活有关。     

参麦注射液对急性缺氧-复氧心肌细胞凋亡的影响

目的：观察参麦注射液对急性缺氧-复氧后心肌细胞凋亡的影响，并探讨其可能机制。 方法： 采用原代培养的大鼠心肌细胞，通过化学缺氧法使细胞缺氧5 min，再恢复氧供应15 min，复制心肌细胞缺氧-复氧（anoxia-reoxygenation, A/R）模型。Annexin V-FITC/PI双染色流式细胞仪检测细胞凋亡百分率；Fluo-3负载激光扫描共聚焦显微镜观察细胞内钙离子水平。 结果： A/R组心肌细胞凋亡百分率明显高于正常组，细胞内平均钙离子荧光强度也显著强于正常组（P<0.01）。参麦注射液组细胞凋亡率显著小于A/R组，同时细胞内钙超载也明显轻于A/R组（P<0.01）。 结论： 参麦注射液能有效抑制缺氧-复氧心肌细胞的凋亡，这种保护作用的机制之一可能是通过减轻细胞内Ca2+超负荷实现的。     

PKCε信号通路介导槲皮素拮抗心肌细胞缺氧/复氧损伤

 目的：探讨槲皮素拮抗心肌细胞缺氧/复氧（A/R）损伤与蛋白激酶Cε(PKCε)之间的关系。方法：培养新生大鼠原代心肌细胞,构建A/R模型,Western　blotting检测槲皮素对PKCε表达水平的调节。检测A/R损伤后各组细胞乳酸脱氢酶活性、肌酸激酶活性、细胞存活率、活性氧（ROS）含量、线粒体膜电位、线粒体通透性转换孔（mPTP）的开放和细胞凋亡。结果：A/R前72 h加入40 μmol/L槲皮素可明显上调心肌细胞PKCε蛋白表达水平,并显著提高细胞存活率,减少ROS产生,维持线粒体膜电位,抑制mPTP开放,减少细胞凋亡（P<0.01）。同时经槲皮素和PKCε抑制剂εV1-2预处理后,则槲皮素的上述保护作用均明显减弱或消失（P<0.01）。结论：槲皮素可以上调心肌细胞PKCε蛋白表达水平,其抗心肌缺血再灌注损伤的保护作用机制可能依赖于PKCε途径。     

HBSP减轻急性缺氧复氧大鼠心肌细胞损伤

目的研究促红细胞生成素衍生肽(HBSP)对急性缺氧/复氧心肌细胞凋亡的影响及其可能的作用机制。方法体外培养H9C2乳鼠心肌细胞系,建立缺氧(3 h)/复氧(3 h)模型。实验分为对照组、缺氧/复氧组(A/R)、A/R+HBSP组。测定培养细胞上清液乳酸脱氢酶(LDH)含量;用annexin-V与PI双染法及流式细胞仪检测心肌细胞凋亡率;分离细胞质与线粒体,用Western blot法检测线粒体内和胞浆中的细胞色素C蛋白的表达,用caspase试剂盒检测心肌细胞caspase-9及caspase-3的表达。结果与正常对照组比较,A/R组细胞存活率和线粒体内细胞色素C蛋白水平明显下降(P0.01),而凋亡率、caspase-9、caspase-3活性及胞质内细胞色素C蛋白水平均显著升高(P0.01)。结论HBSP对缺氧复氧乳鼠心肌细胞具有明显的保护作用,其机制可能与抑制线粒体途径介导的细胞凋亡有关。     

甘氨酸脂质体对心肌细胞线粒体膜电位及凋亡的影响

目的：观察甘氨酸脂质体对缺氧/复氧损伤心肌细胞线粒体膜电位及凋亡的影响。方法:建立培养乳鼠心肌细胞缺氧/复氧(H/R)损伤模型，以DiOC6(3)为荧光分子探针检测实验各组心肌细胞线粒体膜电位；以Annexin V联合PI染色法检测实验各组心肌细胞凋亡率。结果:（1）H/R处理组心肌细胞线粒体膜电位明显低于对照组(P<0.01)，甘氨酸脂质体处理组心肌细胞线粒体膜电位降低最少，弱荧光部分细胞百分率为(9.61±0.76)%。与甘氨酸组比较有显著差异(P<0.01)。（2）H/R处理组心肌细胞凋亡率为(20.78±1.58)%，明显高于对照组(P<0.01)。甘氨酸脂质体处理组心肌细胞凋亡发生率低于甘氨酸组(P<0.01)。空白脂质体组细胞凋亡发生率与H/R组比较差异无统计学意义(P>0.05)。结论:甘氨酸脂质体能抑制培养心肌细胞缺氧/复氧损伤诱导的心肌细胞线粒体膜电位下降和心肌细胞凋亡，脂质体携载甘氨酸能更好发挥其细胞保护作用。     

参麦注射液对AngⅡ诱导培养心肌细胞凋亡的影响

目的:观察参麦注射液对血管紧张素-Ⅱ(AngⅡ)诱导培养心肌细胞凋亡的影响。方法: 乳鼠心肌细胞原代培养,MTT法观察参麦注射液对培养心肌细胞活力的影响;荧光染色、流式细胞仪检测细胞凋亡,Fluo-3荧光探针标记测定钙离子荧光强度。结果: AngⅡ(10^-7mol/L)孵育48 h后心肌细胞凋亡明显多于对照组(P＜0.05);参麦注射液(0.5 g/L、1.0 g/L)组心肌细胞活力显著高于AngⅡ组(P＜0.05);参麦注射液(1.0 g/L)组AngⅡ诱导的心肌细胞凋亡率明显低于AngⅡ组(P＜0.05),AngⅡ所导致的心肌细胞内钙超载明显轻于AngⅡ组(P＜0.01)。结论: 参麦注射液对AngⅡ诱导的细胞凋亡具有明显的抑制作用,其机制可能与其抑制心肌细胞内钙超载有关。     

胰岛素样生长因子I通过改善线粒体功能保护新生大鼠心肌细胞免于凋亡

 目的：探讨线粒体机制在胰岛素样生长因I(IGF-I)保护心肌细胞中的作用。方法：体外培养新生大鼠心肌细胞,过氧化氢处理诱导凋亡,JC-1线粒体膜电位检测法和透射电镜观察心肌细胞线粒体膜电位和形态的改变,Annexin V-FITC/PI双染色法、caspase-3活性测定、DNA-ladder分析和Hoechst 33258染色方法观察心肌细胞凋亡的情况。结果：过氧化氢可诱导心肌细胞凋亡,siRNA下调Kruppel 样因子9（KLF9）48 h后,心肌细胞线粒体膜电位下降率明显降低,由对照组的(24.0±1.6)%,降为IGF-I处理组的(18.3±1.2)%和KLF9下调组的(15.2±1.2)%;线粒体形态明显改善;DNA片段化改善;caspase-3活性降低,与对照组相比IGF-I处理组降低(1.30±0.28)倍,KLF9下调组降低(1.31±0.43)倍;Annexin V-FITC/PI双染法显示细胞凋亡率对照组为（42.5±1.8）%,IGF-I处理组为（22.4±4.2）%,KLF9下调组为（32.5±3.5）%;Hoechst 33258染色结果显示凋亡小体减少,KLF9下调组与IGF-I的抗心肌细胞凋亡效果相似。结论：IGF-I通过下调KLF9表达改善线粒体功能,保护心肌细胞免于凋亡。     

骨髓间质细胞对体外培养的缺氧心肌细胞影响的初步研究

目的：探讨缺氧条件下骨髓间质细胞对培养 的心肌细胞凋亡的作用。方法:共培养乳鼠心肌细胞和骨髓间质细胞。 利用厌养罐模拟细胞缺氧，观察细胞形态、检测细胞凋亡亚二倍体、观察细胞脱氧核苷酸断 裂情况及凋亡相关蛋白的表达。 结果:单独培养的骨髓间质细胞对缺 氧不敏感，而单独培养的心肌细胞在缺氧后24 h出现凋亡，表现为明显的凋亡亚二倍体峰和 “DNA ladder”。当两种细胞缺氧共培养24 h后，混合细胞的凋亡亚二倍体峰明显减少，“ DNA ladder”消失，抗凋亡蛋白Bcl-2表达无显著差异而促凋亡蛋白Bax表达降低。 结论:缺氧条件下体外细胞共培养模型表明骨髓间质细胞对心肌细胞的凋亡有一 定的拮抗作用，可能是通过抑制Bax蛋白的表达而实现的。     

山萘酚、芹菜素对H2O2诱导的心肌细胞凋亡过程中线粒体损伤的影响

目的:观察山萘酚和芹菜素对H2O2诱导的大鼠心肌细胞凋亡过程中线粒体损伤的影响.方法:采用胰蛋白酶消化法,体外分离和培养新生大鼠心肌细胞,建立H2O2损伤心肌细胞模型.以MTT法检测心肌细胞活力,流式细胞仪检测心肌细胞凋亡情况,JC-1荧光探针测定线粒体膜电位,Western blotting法检测胞浆中细胞色素C(Cyt C)的表达.结果:与模型组比较,山萘酚和芹菜素能显著提高心肌细胞活力,降低心肌细胞凋亡率,抑制线粒体膜电位下降和Cyt C释放.结论:山萘酚和芹菜素对H2O2诱导的心肌细胞凋亡具有明显的抑制作用,山萘酚的抗氧化作用强于芹菜素,其机制可能依赖于抑制线粒体膜电位降低和Cyt C释放.     

红景天甙对缺氧/缺糖损伤的SH-SY5Y细胞线粒体膜电位的影响

目的:观察红景天甙对SH-SY5Y 细胞缺氧/缺糖损伤时细胞内[Ca²⁺]i、细胞凋亡率、细胞线粒体膜电位和活性的变化,探讨其对神经细胞线粒体膜电位的影响。方法:应用细胞培养,四唑盐比色实验( MTT )检测细胞线粒体活性,流式细胞术检测细胞内[Ca²⁺]i、细胞凋亡百分率和线粒体膜电位。结果: SH-SY5Y细胞缺氧/缺糖损伤2、4、6、12 h后,细胞内[Ca²⁺]i和细胞凋亡百分率明显高于对照组, 均有显著差异(P<0.01);细胞经缺氧/缺糖处理后,线粒体膜电位和活性明显低于对照组,2 h时分别为29.17%(P<0.01),38.80% (P<0.01), 12 h时分别为56.72%(P<0.01), 63.58% (P<0.01);红景天甙能显著降低细胞内[Ca²⁺]i,抑制细胞凋亡的发生,提高线粒体膜电位和活性,与缺氧/缺糖损伤组相比均有显著差异(P<0.05,P<0.01)。结论:红景天甙可抑制缺氧/缺糖损伤所致的线粒体膜电位和活性的降低,从而具有稳定线粒体膜电位的作用,抑制细胞凋亡的发生,这种作用可能与其能抑制神经细胞内钙超载有关。     

PERK通路参与了缺氧心肌细胞的内质网应激及凋亡

目的:观察缺氧对原代培养的Wistar乳鼠心肌细胞的损伤,探讨内质网应激在缺氧心肌损伤发生发展过程中起的作用及PERK通路是否参与其信号转导过程。方法:将原代培养的乳鼠心肌细胞随机分为正常对照组和缺氧1h、4h、8h、12h、24h组,通过测定细胞ATP含量反映细胞活力;高内涵分析细胞成像系统检测多参数凋亡;采用免疫细胞化学和蛋白印迹方法检测以内质网为靶点的分子伴侣(GRP78和钙网蛋白)的表达,PERK通路(PERK和eIF2α)的磷酸化水平,以及其下游分子(ATF4和CHOP)在缺氧不同时点蛋白的表达变化特征。采用PERK通路激活型药物salubrinal处理原代培养的Wistar乳鼠心肌细胞,观察药物是否对缺氧损伤的心肌细胞有保护作用。结果:缺氧引起心肌细胞凋亡,缺氧早期(约1h)钙网蛋白和GPR78的表达上调;缺氧中期(4h)p-PERK、p-eIF2α和ATF4的表达上调;缺氧后期(12h)CHOP的表达上调。Salubrinal对缺氧心肌有保护作用。结论:在培养的心肌细胞中,缺氧可激发内质网应激。在缺氧早期激活PERK通路保护机体对抗缺氧损伤,后期激活细胞凋亡通路。     

缺氧后处理大鼠心肌细胞线粒体膜电位和细胞凋亡的变化及MS-PPOH对其的影响

目的:观察缺氧后处理(HPO)对大鼠心肌细胞线粒体去极化和细胞凋亡的保护作用及细胞色素P450(CYP450)表氧化酶抑制剂N-methylsulfonyl-6-(2-propargyloxyphenyl)hexanamide(MS-PPOH)对其的影响。方法:采用消化贴壁法分离乳鼠原代心肌细胞,采用缺氧3h、复氧2h方法复制心肌细胞缺氧/复氧(H/R)模型。随机分为四组:对照组(CON组)、H/R模型组(H/R组)、缺氧后处理组(HPO组)、HPO+MS-PPOH组。采用MTT检测心肌细胞存活率;采用高效液相色谱(HPLC)检测心肌培养液11,12-环二十碳三烯酸(11,12-EET)水平;采用线粒体膜电位探针(JC-1)染色检测线粒体膜电位,采用Hoechst染色和TUNEL检测心肌细胞凋亡率。结果:与H/R组比较,HPO组心肌细胞存活率明显增加(P0.01),11,12-EET水平显著升高(P0.05),线粒体膜电位去极化程度明显降低(P0.01),心肌细胞凋亡率显著减少(P0.01);而加入抑制剂后的HPO组,上述指标呈现相反的变化。结论:HPO可能通过减轻心肌细胞线粒体膜电位去极化程度以及减少心肌细胞凋亡而拮抗心肌H/R损伤。     

Apoptosis-resistance of hypoxic cells: multiple factors involved and a role for IAP-2

Hypoxia is an important pathogenic factor in ischemic disease and tumorigenesis. Under hypoxia, some cells are irreversibly damaged, whereas others adapt to the stress and may become more resistant to injury. The mechanism underlying such adaptive responses is unclear. Our recent study showed hypoxic induction of inhibitor of apoptosis protein-2 (IAP-2). Here we have investigated the critical steps in the apoptotic cascade that are affected by hypoxia and have identified a role for IAP-2 in apoptosis resistance of hypoxic cells. The results show that cells cultured in hypoxia became resistant to staurosporine-induced apoptosis. Apoptosis resistance of these cells took place at the mitochondria and in the cytosol. At the mitochondrial level, membrane accumulation of the proapoptotic molecule Bax was suppressed. This was accompanied by less cytochrome c (cyt. c) release from the organelles. In the cytosol, hypoxia induced IAP-2; the cytosol with IAP-2 was resistant to cyt. c-stimulated caspase activation. Of significance, immunodepletion of IAP-2 from the hypoxic cytosol restored its competence for caspase activation. Thus, death resistance of hypoxic cells involves multiple factors targeting different stages of apoptosis, with IAP-2 suppressing caspases in the cytosol.     

乙醛脱氢酶2在大鼠心肌缺氧损伤中的抗凋亡作用

目的： 检测大鼠心肌在缺氧条件下发生细胞凋亡的变化，以及乙醛脱氢酶2（ALDH2）在此过程中所起的作用。 方法： 运用缺氧模型，比较大鼠心肌细胞在单独缺氧和经ALDH2特异性抑制剂daidzin预处理24 h后缺氧的凋亡改变，酶活性检测采用乙醛代谢法、凋亡的测定通过用Hoechest 33324、免疫荧光标记用流式细胞仪测定和TUNEL试剂盒检测。 结果： 心肌细胞在daidzin作用下，其酶活性被抑制而细胞无凋亡发生。在daidzin预处理24 h后再经缺氧诱导，比单独缺氧引起的心肌细胞凋亡更为明显：表现为在Hoechest 33324染色中，细胞核溶解和核碎裂(P<0.05)，FACS和TUNEL显示，凋亡细胞明显增加(P<0.05)。 结论： ALDH2酶活性降低可增加心肌细胞对缺氧导致凋亡的易感性，ALDH2对缺氧引起的细胞凋亡有拮抗作用。     

Changes in antioxidant enzymes in isolated cardiac myocytes subjected to hypoxia-reoxygenation.

BACKGROUND: Intracellular antioxidants have been shown to be depressed during hypoxia, and recovery upon reoxygenation has been correlated with the available antioxidant reserve. To test whether these antioxidant changes are also occurring at the cardiac myocytes level, we studied changes in antioxidant enzyme activities as well as cell injury in isolated cardiac myocytes exposed to hypoxia and reoxygenation. EXPERIMENTAL DESIGN: Isolated Ca(2+)-tolerant myocytes from adult male rats were subjected to 30 minutes hypoxia and 15 minutes reoxygenation. Antioxidant enzymes superoxide dismutase, glutathione peroxidase, catalase; lipid peroxide content; electrolytes (Na+, Ca2+); morphology; and high energy phosphates (ATP, ADP, AMP, creatinine phosphate) were studied in these myocytes. The effects of exogenous catalase (40 units/ml) on hypoxia-reoxygenation induced changes in myocytes were also studied. RESULTS: Hypoxia resulted in a reduction in Mn superoxide dismutase and glutathione peroxidase activities with no change in CAT activity and malondialdehyde content. Reoxygenation of hypoxic cells resulted in recovery of Mn superoxide dismutase but not in glutathione peroxidase activity. Reoxygenation was without any effect on catalase activity, but a significant increase in the malondialdehyde content was seen. Hypoxia as well as reoxygenation caused a reduction in the number of rod-shaped cells with a parallel increase in hypercontracted as well as round cells. There was a significant increase in the myocyte Na+ and Ca2+ content during both hypoxia and reoxygenation, and this was accompanied by leakage of lactate dehydrogenase into the perfusion medium. These changes due to hypoxia and reoxygenation were significantly attenuated by addition of catalase (40 units/ml). High energy phosphates ATP, ADP, and AMP declined during hypoxia, and creatine phosphate was significantly reduced during reoxygenation. CONCLUSIONS: Hypoxia induces specific antioxidant changes in the isolated cardiac myocytes. Reduced ability to remove hydrogen peroxide appears to be an important determinant of myocyte injury during reoxygenation.     

shRNA沉默 ROCK1和ROCK2 表达对缺氧诱导的大鼠心肌细胞凋亡的影响

目的: 探讨Rho相关的卷曲蛋白激酶(ROCK1)和ROCK2在缺氧诱导的大鼠心肌细胞凋亡中的作用。方法: 原代培养大鼠心肌细胞,并用抗α-横纹肌肌动蛋白免疫组化法进行鉴定。将ROCK1-shRNA和ROCK2-shRNA瞬时转染细胞,48 h后给予缺氧6 h处理。实验分为5组:(1)空白对照组;(2)缺氧组;(3)缺氧+阴性对照shRNA组;(4)缺氧+ROCK1-shRNA组;(5)缺氧+ROCK2-shRNA组。用倒置显微镜观察心肌细胞搏动频率与节律;用全自动生化分析仪测定细胞培养液中乳酸脱氢酶(LDH)含量;用MTT检测细胞存活率;用流式细胞仪检测细胞凋亡率;用Western blotting检测ROCK1和ROCK2的表达,并检测caspase-3和p-PI3K的表达情况。结果: 鉴定证实大鼠心肌细胞原代培养成功。缺氧损伤后心肌细胞搏动频率较对照组明显减慢,搏动幅度减弱,节律不规整(P<0.01),而ROCK1-shRNA和ROCK2-shRNA的转染能抑制缺氧导致的这一作用(P<0.05或P<0.01)。全自动生化分析仪检测发现,缺氧能导致细胞培养液LDH含量升高(P<0.01),而ROCK1-shRNA和ROCK2-shRNA的转染能抑制缺氧导致的这一作用(P<0.01)。MTT检测发现,缺氧能导致心肌细胞存活率降低(P<0.05),而ROCK1-shRNA和ROCK2-shRNA的转染能抑制缺氧导致的这一作用(P<0.05)。流式细胞仪检测发现,缺氧能导致心肌细胞凋亡率升高(P<0.01),而ROCK1-shRNA和ROCK2-shRNA的转染能抑制缺氧导致的这一作用(P<0.05或P<0.01)。Western blotting检测发现,ROCK1-shRNA的转染能降低ROCK1的表达(P<0.05), ROCK2-shRNA的转染能降低ROCK2的表达(P<0.01);缺氧能导致caspase-3表达升高(P<0.05)、p-PI3K表达降低(P<0.01),ROCK1-shRNA和ROCK2-shRNA的转染能抑制缺氧导致的这一作用(P<0.05或P<0.01)。结论: ROCK1和ROCK2表达下调能抑制缺氧损伤导致的大鼠心肌细胞凋亡,其机制与抑制caspase-3活化和增强p-PI3K的表达有关。     

Acute lung injury: apoptosis in effector and target cells of the upper and lower airway compartment

Apoptotic cell death has been considered an underlying mechanism in acute lung injury. To evaluate the evidence of this process, apoptosis rate was determined in effector cells (alveolar macrophages, neutrophils) and target cells (tracheobronchial and alveolar epithelial cells) of the respiratory compartment upon exposure to hypoxia and endotoxin stimulation in vitro. Cells were exposed to 5% oxygen or incubated with lipopolysaccharide (LPS) for 4, 8 and 24 h, and activity of caspase‐3, ‐8 and ‐9 was determined. Caspase‐3 of alveolar macrophages was increased at all three time‐points upon LPS stimulation, while hypoxia did not affect apoptosis rate at early time‐points. In neutrophils, apoptosis was decreased in an early phase of hypoxia at 4 h. However, enhanced expression of caspase‐3 activity was seen at 8 and 24 h. In the presence of LPS a decreased apoptosis rate was observed at 8 h compared to controls, while it was increased at 24 h. Tracheobronchial as well as alveolar epithelial cells experienced an enhanced caspase‐3 activity upon LPS stimulation with no change of apoptosis rate under hypoxia. While increased apoptosis rate is triggered through an intrinsic and extrinsic pathway in alveolar macrophages, intrinsic signalling is activated in tracheobronchial epithelial cells. The exact pathway pattern in neutrophils and alveolar epithelial cells could not be determined. These data clearly demonstrate that upon injury each cell type experiences its own apoptosis pattern. Further experiments need to be performed to determine the functional role of these apoptotic processes in acute lung injury.     

缺氧易化快速起搏引起的心室肌细胞钙瞬变交替

目的:探讨缺氧对快速起搏诱导的心室肌细胞钙瞬变交替的影响。方法:分离成年SD大鼠心室肌细胞,并将其置于无血清的低氧液中以建立缺氧性心肌损伤的体外模型;采用激光扫描共聚焦显微镜观察心室肌细胞的钙瞬变及钙瞬变交替情况;应用WST-8试剂盒检测心室肌细胞线粒体的功能状况。结果:在正常情况下,成年SD大鼠心室肌细胞呈棒状,低频起搏(60~240min^-1)可引起钙瞬变现象,但不引起钙瞬变交替。当起搏频率增加至(288±27)min^-1时,可诱导钙瞬变交替现象。缺氧处理后,心室肌细胞的形态学无明显改变,但钙瞬变交替的阈值频率降低为(227±26)min^-1,与对照组比较差异具有统计学意义(P<0.05)。另外,缺氧处理还可使线粒体脱氢酶的相对活性从(100.2±8.7)%降低至(57.6±7.5)%,而L-型钙通道阻滞剂可部分抑制缺氧诱导的线粒体脱氢酶活性降低。结论:缺氧处理可易化快速起搏诱导的心室肌细胞钙瞬变交替,而钙瞬变交替可能介导了缺氧引起的线粒体功能受损。