高糖诱导人脐静脉内皮细胞衰老过程中活性氧与二甲基精氨酸二甲胺水解酶-非对称性二甲基精氨酸系统的变化

目的 观察高糖加速内皮细胞衰老过程中细胞内活性氧(ROS)水平与二甲基精氨酸二甲胺水解酶-非对称性二甲基精氨酸(DDAH-ADMA)系统的变化.方法 正常糖浓度培养液(5.5 mmol/L)和高糖培养液(11.0、22.0、33.0 mmol/L)作用于人脐静脉内皮细胞48 h后,用β-半乳糖苷酶染色鉴定衰老细胞,聚合酶链反应-酶联免疫吸附法(PCR-ELISA)检测端粒酶活性,流式细胞仪检测细胞内ROS水平,液质联用仪检测细胞上清液中ADMA含量及DDAH活性.结果 与正常糖浓度组相比,11.0、22.0、33.0 mmol/L高糖浓度组β-半乳糖苷酶染色阳性细胞率明显增高[(7.00±1.73)%、(12.67±2.03)%、(16.00±2.26)%比(4.00±1.33)%,P＞0.05、P＜0.05、P＜0.05],端粒酶活性显著下降[(91.32±4.01)%、(78.44±3.78)%、(56.04±3.35)%比100%,均P＜0.05];随细胞衰老程度加重,细胞内ROS水平(mfi)显著升高(159.84±27.52、188.99±18.77、244.56±20.96比117.11±18.76,P＜0.05或P＜0.01),ADMA水平(μmol/L)显著升高(0.78±0.14、0.88±0.18、1.08±0.15比0.70±0.12,P＞0.05、P＜0.05、P＜0.05),DDAH活性显著下降[(91.32±4.01)%、(78.44±3.78)%、(56.04±3.35)%比100%,均P＜0.05].结论 高糖可加速内皮细胞衰老进程,其机制可能与氧化应激水平增强、抑制DDAH活性使ADMA含量增加有关.

Abstract：

Objective To investigate the changes in reactive oxygen species (ROS) and dimethylarginine dimethylaminohydrolase-asymmetric dimethylarginine (DDAH-ADMA) system in the process of endothelial cell senescence after exposure to high glucose. Methods The human umbilical vein endothelial cells (HUVECs) were cultured with different concentrations of glucose, e.g. 5. 5 mmol/L (normal level),and high levels as 11. 0, 22. 0 and 33. 0 mmol/L. for 48 hours, respectively. Subsequently, SA-β-gal staining was used to evaluate senescence of cells. Telomerase activity was detected by polymerase chain reactionenzyme linked immunosorbent assay (PCR-ELISA). The intracellular ROS level was measured by flow cytometry. The ADMA concentration and DDAH activity were determined with high-performance liquid chromatography. Results Compared with normal glucose concentration group, after the endothelial cells were treated with high glucose concentration (11. 0 - 33. 0 mmol/L) for 48 hours, the number of SA-β-gal positive cells was increased significantly [(7.00±1. 73)%, (12. 67±2. 03)%, (16. 00±2. 26)% vs. (4. 00±1.33)%, P＞0.05, P＜0.05, P＜0.05] and the telomerase activity was inhibited dramatically [(91. 32±4.01)%, (78. 44±3. 78)%, (56. 04±3. 35)% vs. 100%, all P＜0. 05]. The ROS level (mfi) was increased in all high glucose groups (159. 84±27. 52, 188. 99±18. 77, 244. 56±20. 96 vs. 117.11±18. 76, P＜0. 05 or P＜0. 01). At the same time, the ADMA (μmol/L) production was increased (0. 78±0. 14, 0. 88±0.18,1. 08±0.15 vs. 0. 70±0. 12, P＞0. 05, P＜0. 05, P＜0. 05), and DDAH activity was decreased [(91. 32±4.01)%, (78.44±3.78)%, (56. 04± 3. 35)% vs. 100%, all P＜0.05]. Conclusion High glucose can accelerate endothelial cells senescence in dose-dependent manner and the underlying mechanism may be related to an increased oxidative stress and change in DDAH-ADMA system.     

高糖诱导人脐静脉内皮细胞衰老过程中活性氧和一氧化氮合酶／一氧化氮系统的变化

目的 观察高糖加速内皮细胞衰老过程中细胞内活性氧(ROS)水平和一氧化氮合酶/一氧化氮(NOS/NO)系统的变化.方法 将正常浓度糖(5.5 mmol/L)和高浓度糖(分别为11、22、33 mmol/L)培养液作用于人脐静脉内皮细胞48 h后,用β-半乳糖苷酶(β-gal)染色鉴定衰老细胞,用聚合酶链反应-酶联免疫吸附法(PCR-ELISA)检测端粒酶活性,用硝酸盐还原酶法检测细胞上清液总NO水平,用蛋白质免疫印迹法(Western blotting)分析内皮型一氧化氮合酶(eNOS)蛋白表达,用荧光酶标仪检测细胞内NOS活性,用流式细胞仪检测细胞内ROS水平.结果 高糖培养液作用于内皮细胞48 h后,与对照组比较,随糖浓度升高内皮细胞β-gal染色阳性细胞数明显增多,端粒酶活性下降,细胞NO合成减少,NOS活性被抑制,细胞内ROS水平明显升高(P<0.05或P<0.01),但eNOS蛋白表达变化不明显.结论 高糖加速内皮细胞衰老进程,其作用机制可能与增强氧化应激,抑制NOS/NO系统有关.     

非对称性二甲基精氨酸与血液透析中血压变化的研究

目的研究血液透析(Hemodialysis,HD)患者血浆非对称性二甲基精氨酸(Asymmetric dimethylarginine,ADMA)与透析中血压变化的关系。方法经生物电阻抗检测干体质量达标且符合入选标准的维持性血液透析(Maintenance Hemodialysis,MHD)患者31名进入研究,根据血液透析过程中血压波动情况分为年龄相匹配的3组:透析中高血压组(n=11)、低血压组(n=12)和血压平稳组(n=8)。用酶联免疫吸附(Enzyme linked immunosorbent assay,ELISA)法检测患者透析前、后血浆ADMA水平,探讨ADMA与透析中血压变化的关系,并进行组间矿物质骨代谢指标、电解质、营养指标、炎性标记物、血脂水平、脉压差和降压治疗等的比较。结果 31例MHD患者透析前血ADMA均值为3.37±1.48μmol/L,透析后降至1.71±0.80μmol/L(P0.001),均显著高于国外正常参考值。透析中低血压组透析前、后血ADMA值(4.38±1.56μmol/L,2.25±0.83μmol/L)均高于透析中高血压组和血压平稳组,差异有统计学意义(2.70±1.18μmol/L,1.32±0.60μmol/L和2.78±0.88μmol/L,1.43±0.56μmol/L;P=0.006和0.006)。透析中高血压组患者透析中的平均脉压差高于透析中低血压组和血压平稳组(62.41±11.57mmHg,48.80±12.88 mmHg和44.56±8.30 mmHg,P=0.004)。高血压组碱性磷酸酶(ALP)、总胆固醇(TC)、低密度脂蛋白胆固醇(LDL-C)和高敏C-反应蛋白(high-sensitivity c-reactive protein,Hs-CRP)均高于血压平稳组(P值分别为0.036、0.039、0.046、0.046),低血压组同样指标也高于血压平稳组(P值分别为0.046、0.035、0.040、0.004),上述指标在高血压组和低血压组间差异无统计学意义(P0.05)。结论在干体质量达标的MHD患者中,血ADMA水平显著高于正常,透析过程中的血压波动与内皮功能不良、血管僵硬、微炎症状态等密切相关。     

非对称性二甲基精氨酸水平与缺血性脑卒中的相关性

目的 探讨非对称性二甲基精氨酸(asymmetricaldimethylarginine,ADMA)对缺血性脑卒中诊断及病情判断的临床价值.方法 选取88例缺血性脑卒中患者,采用欧洲卒中量表(ESS)进行神经功能缺损评分分为轻度卒中组(31例)、中度卒中组(39例)和重度卒中组(18例).另选30名年龄、性别构成比与患者组差异无统计学意义的健康志愿者为对照组,分别用高效液相色谱联合质谱法测定血浆中ADMA的水平,分析血浆ADMA水平在对照组和缺血性脑卒中各亚组之间的相关性.结果 对照组、轻度卒中组、中度卒中组和重度卒中组的血浆ADMA水平(±s,μmol/L)分别为:1.0±0.10,2.90±0.30,4.82±0.21及6.61±0.23.与对照组血浆ADMA水平比较,患者组各亚组ADMA水平明显升高,其差异有统计学意义(P<0.05);轻度卒中组与中度和重度卒中组的差异有统计学意义(P<0.05);重度组与中度卒中组的差异有统计学意义(P<0.05),与轻度卒中组的差异有统计学显著性意义(P<0.001).结论 血浆ADMA水平与缺血性脑卒中的发病及病变严重程度相关,检测血浆ADMA水平的变化,对缺血性脑卒中的诊断和病情判断、指导治疗有一定的帮助.     

辛伐他汀对非对称性二甲基精氨酸引起的内皮细胞炎症反应的抑制作用

目的:观察辛伐他汀对非对称性二甲基精氨酸(ADMA)引起的人脐静脉内皮细胞(HUVECs)炎症反应的抑制作用,探讨他汀类药物除降脂作用以外的其他抗动脉粥样硬化机制.方法:体外培养的人济静脉内皮细胞,待细胞生长到融合状态时加入不同浓度的ADMA(3、10、30μmol/L)作用48h,观察ADMA对内皮细胞炎症因子产生的影响.不同浓度的辛伐他汀预先孵育20min,然后加入ADMA(30 μmol/L)作用48h,用ELISA法检测上清液中MCP-1、IL-6和TNF-a浓度,比色法检测一氧化氮(NO)含量的变化.结果:ADMA呈剂量依赖性增加上清液中MCP-1、IL-6和TNF-α浓度并降低NO的含量.外源性补充辛伐他汀可逆转ADMA的效应,且呈剂量依赖性(P＜0.05).用一氧化氮合酶抑制剂左旋硝基精氨酸甲酯(L-NAME)抑制一氧化氮合酶降低NO的合成后,可部分取消辛伐他汀的保护作用.结论:ADMA通过诱导炎症反应,引起内皮功能紊乱,其紊乱程度与ADMA的浓度有关;而辛伐他汀能以剂量依赖的方式抑制ADMA诱导的炎症反应,其机制除与其增加NO的合成有关外,可能还有其他物质或途径的参与.     

非对称性二甲基精氨酸对内皮生长晕细胞凋亡和功能的影响

目的:探讨非对称性二甲基精氨酸(ADMA)对内皮生长晕细胞(EOCs)凋亡和功能的影响.方法:密度梯度离心法分离脐血单个核细胞,培养并扩增EOCs,免疫组化法、荧光染色法鉴定其内皮细胞特性.将浓度为0、1、5、10、30μmol/L的ADMA与EOCs作用48 h,流式细胞仪检测细胞凋亡率,DAPI染色观察凋亡细胞核形态变化,并在倒置显微镜下检测细胞的黏附能力和成血管能力.结果:ADMA(1～30μmol/L)呈浓度依赖性的诱导EOCs的凋亡(P<0.01).ADMA处理组于DAPI染色下可见更显著的细胞凋亡形态学改变.除1μmol/L ADMA外,5、10、30 μmol/L ADMA均可抑制EOCs的黏附能力.10 μmol/L ADMA作用组与对照组相比,明显降低细胞成血管能力(P<0.01).结论:ADMA可以诱导体外培养的EOCs发生凋亡并抑制其黏附能力和成血管能力.     

血浆非对称性二甲基精氨酸水平与2型糖尿病视网膜病变的关系

非对称性二甲基精氨酸(asymmetric dimethylarginine,ADMA)是一个内源性一氧化氮合成酶(nitric oxide synthesis,NOS)抑制剂,它可通过抑制一氧化氮(NO)的产生,影响血管内皮功能[1].     

非对称性二甲基精氨酸与冠心病的相关性研究进展

<正>非对称性二甲基精氨酸(ADMA)是精氨酸甲基化的衍生物,广泛分布于人体的组织细胞及体液中。ADMA是内源性一氧化氮合酶(e NOS)主要的抑制剂,而e NOS为合成一氧化氮(NO)所必需[1]。研究表明,血浆ADMA浓度升高会使NO的合成受抑,导致血管内皮功能障碍和动脉粥样硬化。1非对称性二甲基精氨酸的生成与代谢ADMA是含甲基化精氨酸残基的蛋白质,由特     

辛伐他汀抑制高糖诱导人脐静脉内皮细胞的凋亡

背景：他汀类药物对血管内皮细胞的凋亡是否有影响目前尚不明确。目的：探讨辛伐他汀对高糖诱导的人脐静脉内皮细胞凋亡的影响。方法：用DMEM细胞培养液培养人脐静脉内皮细胞,将细胞分成空白对照组、高糖组和高糖＋辛伐他汀组,用四甲基偶氮唑蓝比色法测定人脐静脉内皮细胞的存活率,流式细胞仪和Westernblot分别检测细胞早期凋亡率及P53蛋白表达。结果与结论：高糖组及高糖＋辛伐他汀组细胞增殖率较空白对照组明显降低（P〈0.01）,而高糖组细胞增殖率较高糖＋辛伐他汀组亦降低（P〈0.01）;高糖组P53蛋白表达量及凋亡率较空白对照组及高糖＋辛伐他汀组明显增加（P〈0.01）,高糖＋辛伐他汀组P53蛋白表达及凋亡率亦明显高于空白对照组（P〈0.01）。表明高糖可通过促进促凋亡蛋白P53的表达进而促进人脐静脉内皮细胞的凋亡,而辛伐他汀可抑制此作用。     

辛伐他汀抑制高糖诱导人脐静脉内皮细胞的凋亡

背景:他汀类药物对血管内皮细胞的凋亡是否有影响目前尚不明确.目的:探讨辛伐他汀对高糖诱导的人脐静脉内皮细胞凋亡的影响.方法:用DMEM 细胞培养液培养人脐静脉内皮细胞,将细胞分成空白对照组、高糖组和高糖+辛伐他汀组,用四甲基偶氮唑蓝比色法测定人脐静脉内皮细胞的存活率,流式细胞仪和Western blot 分别检测细胞早期凋亡率及P53 蛋白表达.结果与结论:高糖组及高糖+辛伐他汀组细胞增殖率较空白对照组明显降低(P < 0.01),而高糖组细胞增殖率较高糖+辛伐他汀组亦降低(P < 0.01) ;高糖组P53 蛋白表达量及凋亡率较空白对照组及高糖+辛伐他汀组明显增加(P <0.01),高糖+辛伐他汀组P53 蛋白表达及凋亡率亦明显高于空白对照组(P < 0.01).表明高糖可通过促进促凋亡蛋白P53 的表达进而促进人脐静脉内皮细胞的凋亡,而辛伐他汀可抑制此作用.     

Erythropoietin prevents reactive oxygen species generation and renal tubular cell apoptosis at high glucose level

Erythropoietin (EPO) can induce a series of cytoprotective effects in many non-hematopoietic tissues through interaction with the erythropoietin receptor (EPOR), but whether EPO can prevent the overproduction of reactive oxygen species (ROS) and apoptosis in diabetes remains unclear. Here, we report that renal tubular cells possess EPOR and that EPO reduces high glucose-induced oxidative stress in renal tubular cells. Further, we found that EPO inhibited high glucose-induced renal tubular cell apoptosis and that this protective effect was dependent on reduction of Bax/caspase-3 expression as well as elevation of Bcl-2 expression. Our results suggest that EPO can inhibit high glucose-induced renal tubular cell apoptosis through direct effect on anti-oxidative stress and that EPOR may play a key role in this process.     

Scavenging of reactive oxygen species induced by hyperthermia in biological fluid

The scavenging activity of rat plasma against hyperthermia-induced reactive oxygen species was tested. The glutathione-dependent reduction of a nitroxyl radical, 4-hydroxyl-2,2,6,6-tetramethylpiperidine-N-oxyl, which was restricted by adding superoxide dismutase or by deoxygenating the reaction mixture, was applied to an index of superoxide (O₂^•−) generation. A reaction mixture containing 0.1 mM 4-hydroxyl-2,2,6,6-tetramethylpiperidine-N-oxyl and 1 mM glutathione was prepared using 100 mM phosphate buffer containing 0.05 mM diethylenetriaminepentaacetic acid. The reaction mixture was kept in a screw-top vial and incubated in a water bath at 37 or 44°C. The time course of the electron paramagnetic resonance signal of 4-hydroxyl-2,2,6,6-tetramethylpiperidine-N-oxyl in the reaction mixture was measured by an X-band EPR spectrometer (JEOL, Tokyo, Japan). When the same experiment was performed using rat plasma instead of 100 mM PB, the glutathione-dependent reduction of 4-hydroxyl-2,2,6,6-tetramethylpiperidine-N-oxyl, i.e., generation of O₂^•−, was not obtained. Only the first-order decay reduction of 4-hydroxyl-2,2,6,6-tetramethylpiperidine-N-oxyl, which indicates direct reduction of 4-hydroxyl-2,2,6,6-tetramethylpiperidine-N-oxyl, was obtained in rat plasma. Adding 0.5% albumin to the phosphate buffer reaction mixture could almost completely inhibit O₂^•− generation at 37°C. However, addition of 0.5% albumin could not inhibit O₂^•− generation at 44°C, i.e., hyperthermic temperature. Ascorbic acid also showed inhibition of O₂^•− generation by 0.01 mM at 37°C, but 0.02 mM or more could inhibit O₂^•− generation at 44°C. A higher concentration of ascorbic acid showed first-order reduction, i.e., direct one-electron reduction, of 4-hydroxyl-2,2,6,6-tetramethylpiperidine-N-oxyl. Hyperthermia-induced O₂^•− generation in rat plasma can be mostly inhibited by albumin and ascorbic acid in the plasma.     

三种抗癌剂诱导肿瘤细胞凋亡与活性氧产生关系的研究

目的 探讨抗癌剂、活性氧、凋亡三者之间的关系,从而进一步探讨抗癌剂的作用及肿瘤细胞耐药机制以及活性氧在肿瘤发生上的意义。方法 用足叶乙甙（Vp16）、阿霉素（ADR）、顺铂（DDP0作用于K562细胞,用流式细胞仪检测三种抗癌剂在不同浓度、作用24h对K562细胞活性氧产生的影响及对凋亡的影响。同时用形态学方法观察凋亡细胞的形态改变。结果 ①Vp16、ADR、DDP三种抗癌剂均可通过激发K562细胞产生活性氧来诱导该细胞发生凋亡;②每种抗癌剂激发K562细胞产生活性氧及诱发该细胞凋亡各有其最适浓度(Vp16为5μg/ml,ADR为3μg/ml,DDP为μg/ml）及最佳作用时间（24h）。结论 流式细胞仪（FCM）测定细胞内活性氧产生状态及细胞凋亡情况,方法具有敏感、快速、简便、只需微量血、可除去坏死细胞碎片等优点。可用于抗癌剂的筛选,指导临床用药及选择敏感抗癌剂的有效剂量及最佳时间,并为探索治疗肿瘤新方法提供一个思路。     

Resveratrol protects primary rat hepatocytes against necrosis induced by reactive oxygen species

Reactive oxygen species can be important mediators of damage to cell molecules and structures. Besides the endogen antioxidant defences, the antioxidant intake in the diet has an important role in the protection against the development of diseases produced by oxidative damage. Resveratrol is a naturally occurring compound present in many plants some of which are part of the human diet. This molecule has been thoroughly investigated because of its antioxidant and anticarcinogenic properties among others. We investigated whether resveratrol could provide protective antioxidant action in primary rat hepatocyte cultures. Primary rat hepatocytes cultures were exposed to 300 μM tert-butyl hydroperoxide; 25, 50 or 75 μM resveratrol or to 300 μM tert-butyl hydroperoxide plus 25, 50 or 75 μM resveratrol for different time periods. Necrosis was evaluated by lactate dehydrogenase liberation to the medium. Apoptosis was evaluated by caspase 3 activity measurement. Changes in cellular morphology after the different treatments were recorded using bright field microscopy. Inhibition of the reactive oxygen species by resveratrol was studied by confocal microscopy and spectrofluorimetrically. Resveratrol inhibited necrosis induced by tert-butyl hydroperoxide. No apoptosis was observed in any treatment. It also was effective in eliminating reactive oxygen species. At 75 μM, the highest concentration tested, resveratrol became slightly cytotoxic. Our results show that resveratrol protects primary rat hepatocytes in culture from oxidative stress induced cell death. These results suggest that resveratrol could enhance the antioxidant status of hepatic cells.     

人视网膜色素上皮细胞诱导型一氧化氮合酶和活性氧在高糖状态下的表达

背景：高血糖导致的自由基损伤是糖尿病视网膜病变发病机制的中心环节。目的：观察高糖对体外培养的人视网膜色素上皮细胞的氧化损伤作用以及高糖对人视网膜色素上皮细胞诱导型一氧化氮合酶和活性氧表达的影响。方法：将培养人视网膜色素上皮细胞,分为对照组、高糖组和甘露醇组,分别用含5.5mmol/L葡萄糖,33mmol/L葡萄糖及5.5mmol/L葡萄糖和27.5mmol/L甘露醇的DMEM培养液培养。采用相差倒置显微镜观察细胞生长形态,采用免疫荧光染色研究诱导型一氧化氮合酶和3-硝基酪氨酸蛋白表达的变化,用氯甲基二氯二氢荧光素二乙酯荧光染色检测视网膜色素上皮细胞中活性氧的产生量。结果与结论：与对照组相比,应用含33mmol/L葡萄糖的DMEM培养基处理视网膜色素上皮细胞48h可见细胞胞体变薄,形态表现多样,不规则细胞增多;高糖培养的视网膜色素上皮细胞诱导型一氧化氮合酶和3-硝基酪氨酸蛋白表达增加,活性氧产生明显增多。说明高浓度葡萄糖培养可造成人视网膜色素上皮细胞氧化损伤,使细胞形态发生变化,并导致细胞中3-硝基酪氨酸产生增多。     

人视网膜色素上皮细胞诱导型一氧化氮合酶和活性氧在高糖状态下的表达

背景:高血糖导致的自由基损伤是糖尿病视网膜病变发病机制的中心环节.目的:观察高糖对体外培养的人视网膜色素上皮细胞的氧化损伤作用以及高糖对人视网膜色素上皮细胞诱导型一氧化氮合酶和活性氧表达的影响.方法:将培养人视网膜色素上皮细胞,分为对照组、高糖组和甘露醇组,分别用含5.5 mmol/L葡萄糖,33 mmol/L葡萄糖及5.5 mmol/L葡萄糖和27.5 mmol/L甘露醇的DMEM培养液培养.采用相差倒置显微镜观察细胞生长形态,采用免疫荧光染色研究诱导型一氧化氮合酶和3-硝基酪氨酸蛋白表达的变化,用氯甲基二氯二氢荧光素二乙酯荧光染色检测视网膜色素上皮细胞中活性氧的产生量.结果与结论:与对照组相比,应用含33 mmol/L葡萄糖的DMEM培养基处理视网膜色素上皮细胞48 h可见细胞胞体变薄,形态表现多样,不规则细胞增多;高糖培养的视网膜色素上皮细胞诱导型一氧化氮合酶和3-硝基酪氨酸蛋白表达增加,活性氧产生明显增多.说明高浓度葡萄糖培养可造成人视网膜色素上皮细胞氧化损伤,使细胞形态发生变化,并导致细胞中3-硝基酪氨酸产生增多.     

Tissue injury by reactive oxygen species and the protective effects of flavonoids

Summary— Reactive oxygen species contribute decisively to a great variety of diseases. Flavonoids are benzo-γ-pyrone derivatives of plant origin found in various fruits and vegetables but also in tea and in red wine. Some of the flavonoids, such as quercetin and silibinin, can effectively protect cells and tissues against the deleterious effects of reactive oxygen species. Their antioxidant activity results from scavenging of free radicals and other oxidizing intermediates, from the chelation of iron or copper ions and from inhibition of oxidases. For their free radical scavenging properties, scavenging of lipid- and protein-derived radicals is presumably of special importance. A non-radical reactive oxygen species effectively trapped by flavonoids is hypochlorous acid. In general, the antioxidative properties of flavonoids are favoured by a high degree of OH substitution. On the other hand, inhibition of enzymatic functions other than oxidases, eg, inhibition of lipoxygenase and thus prevention of the formation of leukotrienes, may also participate in the cell and tissue protective properties of flavonoids.