过氧化作用与肝脏疾病

肝脏疾病中,过氧化通常被定义为强氧化复合物和抗氧化防御之间的不平衡,过量的过氧化产物是肝脏疾病的重要标志物.活性氧是一种机体代谢反应的活性产物,他可以造成很多细胞内分子如膜脂、蛋白和DNA损伤.氧化作用在肝脏疾病发病机制中有着重要意义.本文总结氧化作用自由基的特点以及部分抗氧化剂的特性,并且讨论了氧化作用产物在肝脏疾病中的重要意义.     

肝脏疾病细胞铁死亡研究进展

目的 铁死亡是一种新发现的细胞死亡方式,是由于细胞内铁离子水平异常升高,导致氧化还原失衡,细胞膜发生脂质过氧化,最终细胞膜破裂,导致细胞死亡。目前认为铁死亡的中心环节是铁代谢和活性氧代谢。铁死亡可以影响多种疾病的发生发展过程,例如神经退行性疾病、肿瘤、缺血再灌注损伤、免疫性疾病等。越来越多的研究表明,在多种肝脏疾病的发生发展过程中均出现不同程度的铁超载和脂质活性氧堆积等铁死亡特征。铁死亡可以通过调节细胞内铁离子水平和脂质过氧化程度影响肝脏疾病的进程。本文将针对肝脏疾病发病过程中细胞铁死亡研究进展进行综述。     

Beneficial Effects of Fluvastatin on Liver Microcirculation and Regeneration After Massive Hepatectomy in Rats

Fluvastatin, the first entirely synthetic statin, has a significant cholesterol-lowing effect comparable with other statins. In addition, it has been shown to inhibit oxidative stress and improve vascular endothelial function. The aim of this study was to clarify the pretreatment effects of fluvastatin on liver function after massive hepatectomy in rats. Six-week-old male Wister rats were divided into two groups: a fluvastatin group (group F), pretreated with oral administration of fluvastatin (20 mg/kg per day) for 2 days before 90% hepatectomy; and a control group (group C), pretreated with vehicle for 2 days before hepatectomy. Animals were sacrificed at 0, 12, 24, 48, and 72 h after hepatectomy. The liver regeneration rate, liver function tests, and hepatic stellate cell activation were examined. The liver regeneration rate in group F was significantly higher at 72 h after hepatectomy (P < 0.05). The serum level of total bilirubin in group F was significantly lower at 48 h after hepatectomy (P < 0.05). Sinusoidal area in group F was maintained histologically. Furthermore, the expression of alpha smooth-muscle actin (α-SMA) protein in the liver was inhibited in group F at 48 h after hepatectomy. This study demonstrated the beneficial effects of fluvastatin in a lethal massive hepatectomy model using rats, with improved hepatic regeneration and microcirculations, by inhibiting the activation of hepatic stellate cells.     

Oxidative stress is bane in chronic liver diseases: Clinical and experimental perspective

Oxidative stress plays an important role in the pathogenesis of various chronic liver diseases (CLD) and increasing evidence have confirmed the contributory role of oxidative stress in the pathogenesis of drugs and chemical-induced CLD. Chronic liver injury is manifested as necrosis, cholestasis, fibrosis, and cirrhosis. Chronic administration of anti-tubercular, anti-retroviral, immunosuppressive drugs is reported to induce free radical generation during their biotransformation in the liver. Further, these reactive intermediates are said to induce profibrogenic cytokines, several inflammatory markers, collagen synthesis during the progression of hepatic fibrosis. Oxidative stress and free radicals are reported to induce activation and proliferation of hepatic stellate cells in the injured liver leading to the progression of CLD. Hence, to counteract or to scavenge these reactive intermediates, several plant-derived antioxidant principles have been effectively employed against oxidative stress and came out with promising results in human and experimental models of CLD. This review summarizes the relationships between oxidative stress and different liver pathogenesis induced by drugs and xenobiotics, focusing upon different chronic liver injury induced by alcohol, antitubercular drugs and hyperactivity of antiretroviral drugs in HIV patients, viral hepatitis infection induced oxidative stress.     

衰老对硝酸酯类药物引起活性氮介质和活性氧介质增高的影响

目的:以往研究显示,硝酸酯类药物和衰老都会引发体内活性氧介质(ROS)和活性氮介质(RNS)的增加,本研究旨在探讨年龄是否会影响硝酸酯类药物的这种促进作用。方法:75例不稳定心绞痛患者,分成32例中年组和43例老年两组。所有患者均给予硝酸酯类药物(50μg/min)48h。在试验开始时和用药48小时时,获取血样标本,对血样中的ROS[丙二醛(MDA),髓过氧化物酶(MPO)和还原性谷胱甘肽(GSH)]和RNS(硝基、亚硝基,NOX;过氧亚硝酸阴离子,ONOO-)]的水平进行检测。结果:硝酸酯类药物的使用,引起中年组血浆MDA水平[用药前(1.22±0.37)nmol/m L,用药后(1.61±0.47)nmol/m L,P0.05]增加60%;老年组MDA水平[用药前(2.07±0.77)nmol/m L,用药后(4.05±0.80)nmol/m L,P0.05],增加140%;GSH两组分别减少了9%和48%;硝酸酯类药物使用前,老年组血浆硝基化酪氨酸(398.29±117.0)nmol/L水平为仅为中年组(296.57±120.48)nmol/L的105%,药物使用48h后,老年组血浆硝基化酪氨酸水平(1 182.30±295.01)nmol/L增高到中年组(610.82±217.36)nmol/L,增高210%。结论:在硝酸酯类药物的使用过程中,除了药物本身增加机体内ROS和RNS,年龄增加能够促进硝酸酯类药物的这种作用。     

黄芩苷对体外氧化应激模型中肝型脂肪酸结合蛋白表达的影响及其意义

目的 研究黄芩苷对体外氧化应激模型中肝型脂肪酸结合蛋白(L-FABP)表达的影响及其意义. 方法 用终浓度为400 μ mol/L的过氧化氢(H2O2) 37℃避光孵育细胞20min,建立体外诱导氧化应激模型.应用甲基噻唑基四唑法(MTT)检测不同浓度黄芩苷作用细胞的存活率,确定24h、48 h黄芩苷的半数中毒浓度(TC50).流式细胞技术检测不同浓度黄芩苷(25、50、100μmol/L)作用后活性氧(ROS)的表达、细胞内超氧化物歧化酶(SOD)和谷胱甘肽(GSH)活性变化,实时PCR和Western blot检测肝细胞内L-FABP基因和蛋白表达.数据分析采用单因素方差分析.结果 根据MTT法得出25、50、100 μ mol/L的黄芩苷作用于细胞24h的存活率为83.60％±3.47％,72.36％±2.18％,70.16％±2.04％,F值为386.24,P＞0.05;作用于细胞48h的存活率为84.93％±3.11％,76.16％±2.45％,72.72％±2.31％,F值为475.92,P＞0.05.直线回归法得出黄芩苷持续作用24h和48h的TC50分别为153.2、170.6μmol/L.在此范围内,用25、50、100μmol/L浓度的黄芩苷分别作用Chang肝细胞24、48 h后,ROS含量24 h分别为37.0±3.30,22.90±3.84,29.60±2.52,F值为70.06,P＜0.05 ; 48h分别为35.77±2.35,21.80±3.10,23.87±1.98,F值为110.92,P＜0.05,而400μ mol/L H2O2组ROS含量24h和48h分别为45.50±3.47,48.80±2.70,以50μmol/L的黄芩苷作用48h效果最为显著.用50μmol/L黄芩苷处理48h后细胞内SOD活性为(51.53±1.91)μ g/mg,GSH为(49.85±1.45) U/mg;与对照组SOD为(26.36±1.23)μ g/mg,GSH为(25.11±1.74) U/mg,F值分别为93.81和92.51,P值均＜0.05).尽管50μmol/L黄芩苷处理48 h后细胞内L-FABP在mRNA水平并无明显变化,但50μmol/L黄芩苷处理48 h后细胞内L-FABP蛋白表达与对照组相比增加约80％.结论 黄芩苷能通过增强L-FABP蛋白表达,增加细胞内SOD和GSH的活性发挥抗氧化作用.     

Control of oxidative stress in hepatocellular carcinoma: Helpful or harmful?

Oxidative stress is becoming recognized as a key factor in the progression of chronic liver disease(CLD) and hepatocarcinogenesis. The metabolically important liver is a major reservoir of mitochondria that serve as sources of reactive oxygen species, which are apparently responsible for the initiation of necroinflammation. As a result, CLD could be a major inducer of oxidative stress. Chronic hepatitis C is a powerful generator of oxidative stress, causing a high rate of hepatocarcinogenesis among patients with cirrhosis. Non-alcoholic steatohepatitis is also associated with oxidative stress although its hepatocarcinogenic potential is lower than that of chronic hepatitis C. Analyses of serum markers and histological findings have shown that hepatocellular carcinoma correlates with oxidative stress and experimental data indicate that oxidative stress increases the likelihood of developing hepatocarcinogenesis. However, the results of antioxidant therapy have not been favorable. Physiological oxidative stress is a necessary biological response, and thus adequate control of oxidative stress and a balance between oxidative and anti-oxidative responses is important. Several agents including metformin and L-carnitine can reportedly control mechanistic oxidative stress. This study reviews the importance of oxidative stress in hepatocarcinogenesis and of control strategies for the optimal survival of patients with CLD and hepatocellular carcinoma.     

活性氧在胃上皮细胞凋亡中的作用

在55例慢性胃炎患者中用化学发光分析法测定了胃上皮细胞中的活性氧(ROS)水平.用TUNEL法测定了胃上皮的细胞凋亡指数(AI),并根据ROS水平将患者分成4组。结果显示.在ROS水平<50组 AI为1.9±0.3:ROS 50～99组,AI为4.7±0.9:ROS 100～400组.AI为6.8±1.1:ROS>400组,AI为5.4±1.5。提示一定水平的ROS可促进细胞凋亡,但过高水平的ROS可能引起细胞坏死而非细胞凋亡。     

寄生性蠕虫过氧化物氧还蛋白研究进展

过氧化物氧还蛋白为广泛存在于需氧生物体的过氧化物酶家族抗氧化蛋白。寄生性蠕虫过氧化物氧还蛋白不仅可以清除虫体自身代谢产生的活性氧族分子(reactive oxygen species,ROS)和活性氮族分子(reactive nitrogen species,RNS),而且在抗御宿主免疫细胞产生的ROS和RNS的潜在损伤中起着至关重要的作用。本文综述了过氧化物氧还蛋白的分类、作用机制以及寄生性蠕虫(包括吸虫、绦虫和线虫)过氧化物氧还蛋白的研究进展。     

寄生性原虫中peroxiredoxin的研究进展

Peroxiredoxin(Prx)属于一个广泛存在的过氧化物酶家族,对许多病原体在有氧环境下的生存起重要作用。该文综述了Prx的结构、分类及其在寄生性原虫中的研究进展。     

Suprahepatic vena cava manipulative bleeding alleviates hepatic ischemia–reperfusion injury in rats

BACKGROUND: Little is known about time course and peak level of reactive oxygen species in suprahepatic vena cava after liver ischemia-reperfusion. OBJECTIVE: To determine time course and peak level of reactive oxygen species in suprahepatic vena cava after liver ischemia-reperfusion. To focus on the effects of suprahepatic vena cava manipulative bleeding on the hepatic ischemia-reperfusion injury in rat model. METHODS: In experiment Part I, blood was taken from suprahepatic vena cava and infrahepatic vena cava for malondialdehyde detection at different time points after reperfusion. Furthermore, we treated the experimental rats in Part II by suprahepatic vena cava manipulative bleeding or infrahepatic vena cava manipulative bleeding at 10 min after reperfusion. RESULTS: In experiment Part I, malondialdehyde concentration in suprahepatic vena cava elevated obviously with time and peaked at 10 min after reperfusion. The numbers of accumulated polymorphonuclear neutrophils was significantly increased in ischemia-reperfusion group from 10 min after reperfusion, compared with sham-operated group. In Part II, 2% of body weight suprahepatic vena cava manipulative bleeding with blood transfusion at 10 min after reperfusion significantly decreased circulating malondialdehyde, tumour necrosis factor-alpha, endothelin-1, hyaluronic acid, alanine aminotransferase, aspartate aminotransferase levels and polymorphonuclear neutrophil infiltrations in the liver. The 7-day survival rate of this group was 68.75% (11/16) which was significantly higher than other groups. CONCLUSIONS: We provided the first evidence that 2% of body weight suprahepatic vena cava manipulative bleeding with blood transfusion at 10 min after reperfusion significantly prevented liver ischemia-reperfusion injury.     

Nitroglycerine causes mitochondrial reactive oxygen species production: in vitro mechanistic insights

BACKGROUND: Nitroglycerine (GTN) is an organic nitrate that has been used for more than 100 years. Despite its widespread clinical use, several aspects of the pharmacology of GTN remain elusive. In a recent study, the authors of the present study showed that GTN causes opening of the mitochondrial permeability transition pore (mPTP) and mitochondrial production of reactive oxygen species (ROS). OBJECTIVE: In the present study, it was tested whether GTN-induced ROS production depends on mitochondrial potassium ATP-dependent channel or mPTP opening, and/or GTN biotransformation. METHODS AND RESULTS: Isolated rat heart mitochondria were incubated with succinate (a substrate for complex II) and GTN, causing immediate ROS production, as manifested by chemiluminescence. This ROS production was prevented by concomitant vitamin C incubation. Conversely, inhibitors of potassium ATP-dependent channels, mPTP opening or of GTN biotransformation did not modify ROS production. CONCLUSIONS: GTN triggers mitochondrial ROS production independently of the opening of mitochondrial channels and/or of GTN biotransformation. The present data, coupled with previous evidence published by the same authors that GTN causes opening of mPTPs, provide further evidence on the pharmacology of GTN. It is proposed that GTN causes direct uncoupling of the respiratory chain, which determines ROS production and subsequent mPTP opening. The clinical implications of these findings are also discussed.     

低氧诱导线粒体自噬的机制及其在相关疾病中的研究进展

线粒体在氧充足的条件下通过氧化磷酸化产生三磷酸腺苷供应机体的能量代谢。当细胞低氧时,线粒体产生大量的活性氧(ROS),导致氧化应激和线粒体功能障碍,从而对组织或细胞造成损伤,导致疾病发生。因此,降低体内的ROS水平对控制疾病、维持机体内稳态至关重要。近些年研究显示细胞在低氧条件下可通过上调低氧诱导因子1、激活BNIP3和BNIP3L/NIX介导的通路、线粒体上FUNDC1受体的可逆磷酸化等机制调控线粒体自噬,清除多余的或受损的线粒体,最终减少ROS的产生。相对地,ROS自身可激活其他多种信号分子,如p62、FOXO3等对细胞自噬进行调节。低氧诱导ROS的损害作用及线粒体自噬的保护作用与呼吸疾病、代谢疾病、肿瘤及神经退行性疾病等疾病密切相关,深入研究低氧诱导线粒体自噬的具体机制有可能为疾病的诊治提供新的方向。本文就低氧诱导线粒体自噬发生的机制及其与相关疾病的关联作一综述。     

叔丁基对苯二酚对亚砷酸钠致细胞毒性和氧化损伤的拮抗作用

目的 探讨叔丁基对苯二酚(tBHQ)对亚砷酸钠(NaAsO2)致细胞毒性和氧化损伤的拮抗作用。方法 Chang肝细胞用tBHQ[0(对照)、5、25μmol/L]预处理24h,再用5 μmol/L tBHQ和NaAsO2[0(对照)、30、40、50、60 μmol/L]共同作用24h,采用刃天青钠(Alamar blue)还原法检测细胞活力,结果用实验组Alamar blue还原率与对照组Alamar blue还原率的相对比值表示;Chang肝细胞用tBHQ[0(对照)、5、25 μmol/L]预处理24h,再用5μmol/L tBHQ和NaAso2[0(对照)、40、50 μmol/L]共同作用24h,采用荧光探针2′,7′-二乙酰二氯荧光素(DCFH-DA)检测细胞内活性氧(ROS)的生成,结果用实验组平均荧光强度与对照组平均荧光强度的相对比值表示。结果 30、40、50、60 μmol/L的NaAsO2暴露能够显著降低细胞活力,而tBHQ预处理(5、25 μmol/L)则可明显恢复细胞活力,NaAsO2和tBHQ两因素的主效应及其交互作用均有统计学意义（F值分别为566.57、55.09、14.50,P均＜0.05）;5、25 μmol/L tBHQ预处理的30、40、50、60 μmol/LNaAsO2组细胞活力(0.75±0.02、0.70±0.04、0.59±0.03、0.43±0.03和0.75±0.02、0.73±0.03、0.65±0.02、0.50±0.02)较相应NaAsO2单独作用组(0.70±0.03、0.64±0.03、0.43±0.03、0.33±0.01)显著升高（P均＜0.05）,25 μmol/L tBHQ 预处理的50、60μmol/L NaAsO2组细胞活力高于相应5μmol/L tBHQ预处理组（P均＜0.05）。40、50 μmol/L的NaAsO2能显著诱导Chang肝细胞内ROS的产生,而tBHQ预处理(5、25 μmol/L)则可使NaAsO2诱导产生的细胞内ROS水平显著下降,NaAsO2和tBHQ两因素的主效应及其交互作用均有统计学意义（F值分别为181.78、60.55、4.93,P均＜0.05）;5、25 μmol/L tBHQ预处理的40、50 μmol/L NaAsO2组细胞内ROS水平(1.87±0.09、1.80±0.07和1.36±0.11、1.44±0.12)较相应NaAsO2单独作用组(2.30±0.18、2.18±0.17)显著降低(P 均＜ 0.05),25 μmol/L tBHQ预处理的40、50 μmol/L NaAsO2组细胞内ROS水平低于相应5μmol/L tBHQ预处理组（P均＜ 0.05）。结论 tBHQ对NaAsO2诱导的细胞毒性和氧化损伤具有一定的拮抗作用。     

氧自由基在老年人造影剂肾病中作用的研究进展

随着我国老龄化进程逐渐加速,冠心病、脑梗死发病率显著升高,其影像诊断、经皮介入治疗时常用含碘造影剂,造影剂以原形从肾小球滤过,且不被肾小管吸收,但造影剂在肾脏积聚可导致急性肾损伤。肾脏是人体最重要的排泄、内分泌器官之一,造影剂肾病(CIN)的防治受到广泛关注。老年人由于各脏器功能增龄性减退,造影剂相关的肾损害发病率高、...     

大黄素诱导肝癌细胞氧化损伤的实验研究

目的：研究大黄素抑制肝癌细胞增殖的作用机理。方法：采用流式细胞仪法观察了大黄素对肝癌细胞内活性氧的影响；采用MTT比色法观察了大黄素对细胞增殖的影响。结果：大黄素作用于肝癌细胞后，在2小时内引起活性氧的产生；大黄素抑制了肝癌细胞的增殖。结论：大黄素能够通过诱导细胞内活性氧的产生，引起细胞脂质过氧化，抑制了肝癌细胞的增殖。