活性氧在二氮嗪预处理减轻大鼠心肌细胞缺氧复氧损伤中的作用

目的探讨活性氧(ROS)在线粒体KATP(Mito-KATP)通道特异性开放剂二氮嗪预处理减轻大鼠心肌细胞缺氧复氧损伤中的作用及其机制。方法培养的成年大鼠心室肌细胞,随机分为5组:对照组、缺氧复氧组、二氮嗪预处理 缺氧复氧组、二氮嗪 ROS清除剂2-硫基丙酰氨基乙酸(MPG)预处理 缺氧复氧组、二氮嗪 蛋白激酶C特异性抑制剂氯化白屈菜赤碱预处理 缺氧复氧组。对照组常规培养;缺氧复氧组缺氧30min复氧40min;其余各组则加入相应的药物预处理10 min,二氮嗪、MPG、氯化白屈菜赤碱的终浓度分别为200、400、2μmol·L-1,更换无血清培养基培养20 min,然后缺氧30 min复氧40 min。采用MTT法、CK检测试剂、Na -K -ATPase活性检测试剂和Western blot等方法分别检测心肌细胞的活力、CK活性、Na -K -ATPase活性、细胞浆和细胞膜PKCε表达情况,计算细胞膜PKCε表达百分比。结果缺氧复氧可导致心肌细胞存活率及Na -K -ATPase活性降低, CK活性升高;二氮嗪预处理能增加细胞存活率及Na -K -ATPase活性,降低CK活性,增加细胞膜PKCε表达百分比;MPG抑制了二氮嗪预处理的心肌保护作用,并且在一定程度上抑制了PKCε的转位;CH可完全阻滞PKCε的转位,并且可降低二氮嗪预处理的心肌保护作用。结论Mito-KATP通道开放后释放的ROS参与了二氮嗪预处理减轻大鼠心肌细胞缺氧复氧损伤,其机制与PKCε的转位激活有关。     

氧自由基在异氟醚诱导小鼠前脑细胞凋亡中的作用

目的 观察小鼠暴露于异氟醚后前脑Caspase-3蛋白和氧自由基的变化,以了解氧自由基(reactive oxygen spceies,ROS)在异氟醚神经损伤中的作用.方法 56只雄性C57BL/6J小鼠按随机数字表法分为异氟醚组(Iso组,n=20)、二甲基硫脲±异氟醚组(DMTU±Iso组,n=8)、二甲基硫脲组...     

Mitochondrial adenosine triphosphate-regulated potassium channel opening acts as a trigger for isoflurane-induced preconditioning by generating reactive oxygen species

BACKGROUND: Whether the opening of mitochondrial adenosine triphosphate-regulated potassium (K(ATP)) channels is a trigger or an end effector of anesthetic-induced preconditioning is unknown. We tested the hypothesis that the opening of mitochondrial K(ATP) channels triggers isoflurane-induced preconditioning by generating reactive oxygen species (ROS) in vivo. METHODS: Pentobarbital-anesthetized rabbits were subjected to a 30-min coronary artery occlusion followed by 3 h reperfusion. Rabbits were randomly assigned to receive a vehicle (0.9% saline) or the selective mitochondrial K(ATP) channel blocker 5-hydroxydecanoate (5-HD) alone 10 min before or immediately after a 30-min exposure to 1.0 minimum alveolar concentration (MAC) isoflurane. In another series of experiments, the fluorescent probe dihydroethidium was used to assess superoxide anion production during administration of 5-HD or the ROS scavengers N-acetylcysteine or N-2-mercaptopropionyl glycine (2-MPG) in the presence or absence of 1.0 MAC isoflurane. Myocardial infarct size and superoxide anion production were measured using triphenyltetrazolium staining and confocal fluorescence microscopy, respectively. RESULTS: Isoflurane (P < 0.05) decreased infarct size to 19 +/- 3% (mean +/- SEM) of the left ventricular area at risk as compared to the control (38 +/- 4%). 5-HD administered before but not after isoflurane abolished this beneficial effect (37 +/- 4% as compared to 24 +/- 3%). 5-HD alone had no effect on infarct size (42 +/- 3%). Isoflurane increased fluorescence intensity. Pretreatment with N-acetylcysteine, 2-MPG, or 5-HD before isoflurane abolished increases in fluorescence, but administration of 5-HD after isoflurane only partially attenuated increases in fluorescence produced by the volatile anesthetic agent. CONCLUSIONS: The results indicate that mitochondrial K(ATP) channel opening acts as a trigger for isoflurane-induced preconditioning by generating ROS in vivo.     

氧自由基在异氟醚诱导小鼠前脑细胞凋亡中的作用

Objective By observing the changes of Caspase-3 protein and reactive oxygen species (ROS) in the forebrain of mice induced by isoflurane inhalation to study the role of ROS in neural damages of isoflurane. Methods Fifty-six male C57BL/6Jmice were randomly divided into isoflurane group(Iso, n=20), dimethylthiourea group(DMTU,n=8), imethylthiourea plus isoflurane group(DMTU+lso, n=8), and control group(Con,n=20). Mice in Iso and DMTU+Iso groups were exposed to three segments of 1.4%isoflurane, 2 h for each segment. Thirty min before oxygen inhalation in DMTU group and first segment of isoflurane inhalation in DMTU+Iso group, 50 mg/kg of radical scavenger DMTU were intraperitoneally injected to the mice in the two groups. The changes of caspase-3 expression in prefrontal cortex were observed by immunocytochemical staining. And the activities of superoxide dismutase (SOD) and the amount of MDA were detected. Results Compared with Con group, the number of caspase-3 positive cells in Iso group increased significantly (3.38 times, P＜0.05); but in DMTU+Iso group( 1.43 times of Con group) and DMTU group(0.74 times of Con group),it did not change obviously (P＞0.05). There was no significant difference in the activities of SOD between Iso group [(25±10) U/mgprot] and Con group [(20±6) U/mgprot](P＞0.05), but lipid peroxidation malondialdehyde (MDA) content in Iso group [(13.7±6.1 ) nmol/mgprot] was significantly higher than that in Con group [(5.7±2.7) nmol/mgprot](P＜0.05). Conclusion 1.4% isoflurane exposure significantly increase the expression of caspase-3 in the forebrain of mice and its molecular mechanism may be related to the increase of free radicals.     

活性氧在骨性关节炎发病中的作用机制（英文）

近年来越来越多的研究表明活性氧在骨性关节炎的发病中起到关键作用,主要涉及到软骨细胞的凋亡和细胞外基质的退化,后者包括基质合成减少、分解增加以及钙化形成。本文就活性氧在骨性关节炎发病机制研究中的进展作一综述。     

Ischemic preconditioning: a defense mechanism against the reactive oxygen species generated after hepatic ischemia reperfusion

BACKGROUND: Preconditioning protects against both liver and lung damage after hepatic ischemia-reperfusion (I/R). Xanthine and xanthine oxidase (XOD) may contribute to the development of hepatic I/R. OBJECTIVE: To evaluate whether preconditioning could modulate the injurious effects of xanthine/XOD on the liver and lung after hepatic I/R. METHODS: Hepatic I/R or preconditioning previous to I/R was induced in rats. Xanthine and xanthine dehydrogenase/xanthine oxidase (XDH/XOD) in liver and plasma were measured. Hepatic injury and inflammatory response in the lung was evaluated. RESULTS: Preconditioning reduced xanthine accumulation and conversion of XDH to XOD in liver during sustained ischemia. This could reduce the generation of reactive oxygen species (ROS) from XOD, and therefore, attenuate hepatic I/R injury. Inhibition of XOD prevented postischemic ROS generation and hepatic injury. Administration of xanthine and XOD to preconditioned rats led to hepatic MDA and transaminase levels similar to those found after hepatic I/R. Preconditioning, resulting in low circulating levels of xanthine and XOD activity, reduced neutrophil accumulation, oxidative stress, and microvascular disorders seen in lung after hepatic I/R. Inhibition of XOD attenuated the inflammatory damage in lung after hepatic I/R. Administration of xanthine and XOD abolished the benefits of preconditioning on lung damage. CONCLUSIONS: Preconditioning, by blocking the xanthine/XOD pathway for ROS generation, would confer protection against the liver and lung injuries induced by hepatic I/R.     

活性氧的内源性心肌保护作用及其机制

既往认为在心肌缺血/再灌注过程中活性氧是一种有害的细胞损伤因子,但最近研究发现也是可产生细胞保护作用的信号分子.活性氧(reactive oxygen species,ROS)在缺血,再灌注及其内源性心肌保护作用中具有双重作用,内源性心肌保护过程中活性氧主要来自线粒体呼吸链,主要通过mKATP-ROS通路产生;活性氧通过改变细胞氧化还原状态和调节线粒体膜通透性转换孔道开放状态,传递线粒体和细胞之间的信息联系.因此.活性氧不单是缺血/再灌注氧化应激的损伤因子,也是产生内源性心肌保护作用的重要信号分子.     

活性氧的内源性心肌保护作用及其机制

既往认为在心肌缺血/再灌注过程中活性氧是一种有害的细胞损伤因子,但最近研究发现也是可产生细胞保护作用的信号分子.活性氧(reactive oxygen species,ROS)在缺血,再灌注及其内源性心肌保护作用中具有双重作用,内源性心肌保护过程中活性氧主要来自线粒体呼吸链,主要通过mKATP-ROS通路产生;活性氧通过改变细胞氧化还原状态和调节线粒体膜通透性转换孔道开放状态,传递线粒体和细胞之间的信息联系.因此.活性氧不单是缺血/再灌注氧化应激的损伤因子,也是产生内源性心肌保护作用的重要信号分子.     

Up-regulation of glomerular COX-2 by angiotensin II: role of reactive oxygen species

BACKGROUND: Prostaglandins such as prostaglandin E(2) (PGE(2)) and prostaglandin I(2) (PGI(2)) counteract the angiotensin II (Ang II)-induced vasoconstriction in the glomerular microcirculation. We have shown that Ang II promotes mesangial cell hypertrophy via reactive oxygen species (ROS), which originate from nicotinamide adenine dinucleotide phosphate and its reduced form (NADH/NADPH) oxidase. It has been reported that conditions associated with activation of the renin-angiotensin system result in increased glomerular cyclooxygenase-2 (COX-2) expression and activity. METHODS: We designed studies to determine (1) whether Ang II induces COX-2 in the glomerulus in vivo in the glomerulus as well as in vitro in mesangial cells, (2) whether ROS originated from Ang II are involved, and (3) whether COX-2-derived prostaglandins modulate the growth promoting effects of Ang II in mesangial cells. Rats were infused with Ang II (0.7 mg/kg/day) for 5 days and glomerular COX-2 expression and activity assessed in isolated glomeruli. RESULTS: Ang II increased glomerular PGE(2) production (100%) accompanied by a concomitant increase in glomerular COX-2 expression at the mRNA (1.7-fold) and protein level (sixfold). In mesangial cells, Ang II significantly increased mesangial cell PGE(2) (200%) and PGI(2) (100%) production as well as COX-2 mRNA that was prevented by the angiotensin type 1 (AT1) receptor blocker irbesartan and the COX-2 inhibitor NS-398. The NADPH oxidase inhibitor diphenyleneiodonium (DPI), the ROS scavenger tiron as well as catalase, inhibited Ang II-induced PGE(2) production suggesting that Ang II-induced ROS mediate COX-2 up-regulation. Strikingly, COX-2 inhibition as well as blockade of the type 1 PGE(2) receptor (EP1) prevented Ang II-induced mesangial cell hypertrophy suggesting that COX-2-derived prostaglandins, and specifically PGE(2), importantly contribute to the growth promoting effects of Ang II. CONCLUSION: These studies suggest that blockade of specific PGE(2) receptors may be a novel strategy to modulate the pathologic effects of COX-2-derived prostaglandins without simultaneously affecting protective vasodilatory mechanisms.     

Preconditioning by isoflurane is mediated by reactive oxygen species generated from mitochondrial electron transport chain complex III

Reactive oxygen species (ROS) mediate volatile anesthetic preconditioning. We tested the hypothesis that isoflurane (ISO) generates ROS from electron transport chain complexes I and III. Rabbits (n = 55) underwent 30 min coronary artery occlusion followed by 3 h reperfusion and received 0.9% saline, the complex I inhibitor diphenyleneiodonium (DPI; 1.5 mg/kg bolus followed by 1.5 mg/kg over 1 h), or the complex III inhibitor myxothiazol (MYX; 0.1 mg/kg bolus followed by 0.3 mg/kg over 1 h) in the absence and presence of 1.0 minimum alveolar concentration ISO. ISO was administered for 30 min and discontinued 15 min before coronary occlusion. Infarct size and ROS production (n = 32) were determined using triphenyltetrazolium staining and ethidium-DNA fluorescence, respectively. Adenosine triphosphate (ATP) synthesis in mitochondria obtained from rabbit hearts (n = 24) subjected to drug interventions was measured by luciferin-luciferase luminometry. ISO significantly (P < 0.05) reduced infarct size (19% +/- 4%) as compared with control (39% +/- 4%). MYX (35% +/- 4%), but not DPI (24% +/- 2%), abolished this protection. ISO increased ethidium-DNA fluorescence (83 +/- 11 U) as compared with control (40 +/- 12 U). MYX (35 +/- 3 U), but not DPI (78 +/- 9 U), abolished ROS generation. DPI and MYX selectively reduced complex I- and complex III-mediated ATP synthesis, respectively. ROS generated from electron transport chain complex III mediate ISO-induced cardioprotection.     

活性氧的内源性心肌保护作用及其机制

既往认为在心肌缺血/再灌注过程中活性氧是一种有害的细胞损伤因子,但最近研究发现也是可产生细胞保护作用的信号分子.活性氧(reactive oxygen species,ROS)在缺血,再灌注及其内源性心肌保护作用中具有双重作用,内源性心肌保护过程中活性氧主要来自线粒体呼吸链,主要通过mKATP-ROS通路产生;活性氧通过改变细胞氧化还原状态和调节线粒体膜通透性转换孔道开放状态,传递线粒体和细胞之间的信息联系.因此.活性氧不单是缺血/再灌注氧化应激的损伤因子,也是产生内源性心肌保护作用的重要信号分子.     

乳化异氟烷预处理对兔心肌缺血再灌注损伤的影响

目的 评价乳化异氟烷预处理对兔心肌缺血再灌注损伤的影响.方法 雄性新西兰白兔32只,体重2.5～3.0 kg,随机分为4组(n=8):缺血再灌注组(IR组)、异氟烷预处理组(I组)、乳化异氟烷预处理组(EI组)和脂肪乳组(INT组).采用结扎左冠状动脉前降支30 min、再灌注180 min的方法建立兔心肌缺血再灌注模型.各组稳定30 min后,I组吸入3%异氟烷,维持呼气末浓度2.20%30 min,洗脱15 min;EI组先以1 ml/s的速率静脉注射8%乳化异氟烷8～10 ml,然后静脉输注6～8 ml·kg-1·h-1,维持呼气末浓度1.28%30 min,洗脱15 min;INT组先以1 ml/s的速率静脉注射30%脂肪乳9 ml,然后静脉输注7 ml·kg-1·h-1持续30 min.于稳定30 min(T0)、缺血前(T1)、缺血即刻(T2)、缺血30 min(T3)、再灌注60 min(T4)、120 min(T5)和180 min(T6)时,记录HR、SP和MAP,计算HR和SP的乘积(RPP).于T6时抽取动脉血样3 ml,测定血清肌酸激酶(CK)、乳酸脱氢酶(LDH)的活性和IL-6、IL-10的浓度,并测定心肌梗死范围.结果 与T0时比较,T2-6时各组HR、MAP和RPP呈进行性下降(P<0.05);四组间HR、MAP和RPP比较差异无统计学意义(P>0.05).与IR组比较,I组和EI组心肌梗死范围减小,血清CK、LDH的活性和IL-6浓度降低,L-10浓度升高(P0.05).结论 乳化异氟烷预处理可减轻兔心肌缺血再灌注损伤,机制可能与其抑制炎性反应有关.     

乳化异氟醚预处理对兔心肌缺血再灌注损伤的影响

目的 探讨乳化异氟醚预处理对兔心肌缺血再灌注损伤的影响.方法 健康雄性新西兰大白兔32只,体重2.0～2.5 kg,阻断冠状动脉1 h,再灌注3 h建立心肌缺血再灌注损伤模型,随机分为4组(n=8),缺血再灌注组(IR组),异氟醚组(Ⅰ组)吸入异氟醚,维持呼气末浓度0.5 MAC 30min,洗脱15 min后缺血1h再灌注3 h;乳化异氟醚组(EI组)静脉注射(1 ml/s)8%乳化异氟醚4～6 ml至呼气末浓度0.5 MAC,以4～6 ml·kg-1·h-1静脉输注乳化异氟醚维持呼气末浓度0.5 MAC 30 min,洗脱15 min后缺血1 h再灌注3 h;脂肪乳组(L组)静脉输注(5 m1·kg-1·h-1)与乳化异氟醚等量的30%脂肪乳注射液30 min,停止静脉输注脂肪乳15 min后缺血1 h再灌注3 h.再灌注3 h后测定血清磷酸肌酸激酶(CK)、乳酸脱氢酶(LDH)活性和一氧化氮(NO)浓度,并计算梗死区心肌与左心室干重比值、梗死区心肌与缺血区心肌干重比值.结果 与IR组比较,Ⅰ组和EI组梗死区心肌与左心室干重比值、梗死区心肌与缺血区心肌干重比值均明显降低,血清CK和LDH活性降低,NO浓度增加(P＜0.05),L组上述指标差异无统计学意义(P＞0.05);Ⅰ组和EI组各指标差异无统计学意义(P＞0.05).结论 8%乳化异氟醚预处理可减轻兔心肌缺血再灌注损伤,其机制可能与NO生成量增加有关.     

活性氧在七氟醚预处理减轻大鼠海马脑片氧糖缺失损伤中的作用

目的 评价活性氧(ROS)在七氟醚预处理减轻大鼠海马脑片氧糖缺失损伤中的作用.方法 雄性SD大鼠,体重80～100 g,断头处死,剥离海马,符合标准的40片海马脑片随机分为4组(n=10):氧糖缺失组(OGD组)、4%七氟醚预处理组(Sevo组)、ROS清除剂组(MPG组)和4%七氟醚预处理+ROS清除剂组(SM组),采用脑片灌流及电生理技术,细胞外记录海马CAI区缺氧期间和复氧1 h期间的顺向群锋电位(OPS);采用2,3,5-三苯基氯化四氮唑(TYC)染色定量比色法分析脑片损伤程度.结果 与OGD组相比,Sevo组OPS消失时间缩短,OPS恢复程度、OPS恢复率均升高,组织损伤百分率降低(P<0.01);与Sevo组相比,MPG组和SM组OPS消失时间缩短,OPS恢复程度、OPS恢复率降低,组织损伤百分率升高(P相似文献   

Anesthetic preconditioning improves adenosine triphosphate synthesis and reduces reactive oxygen species formation in mitochondria after ischemia by a redox dependent mechanism

BACKGROUND: Mitochondrial changes that characterize the heart after anesthetic preconditioning (APC) or the mechanisms by which mitochondrial triggering factors lead to protection are unknown. This study hypothesized that generation of reactive oxygen species (ROS) during APC is required to initiate the mitochondrial protective effects, and that APC leads to improved mitochondrial electron transport chain function and cardiac function during reperfusion. METHODS: Isolated guinea pig hearts were subject to 30 min ischemia and 120 min reperfusion. Prior to ischemia hearts were either untreated (I/R), or treated with sevoflurane (APC), in the presence or absence of the ROS scavenger tiron (TIR), or the superoxide dismutase mimetic MnTBAP (TBAP). Intracellular ROS were measured by spectrofluorometry using the fluorescent probe dihydroethidium (DHE). In another series of experiments, using the same protocol, hearts were reperfused for only 5 min and removed for measurement of adenosine triphosphate (ATP) synthesis by luciferin-luciferase luminometry and ROS generation by dichlorohydro-fluorescein (DCF) fluorescence in isolated mitochondria. RESULTS: The APC improved cardiac function and reduced infarction. Tiron or MnTBAP abrogated the protection afforded by APC. Mitochondrial ATP synthesis was decreased by 70 +/- 3% after IR alone, by only 7 +/- 3% after APC, by 69 +/- 2% after APC+TIR, and by 71 +/- 3% after APC + TBAP. Mitochondrial ROS formation (DCF) increased by 48 +/- 3% after IR alone, by 0 +/- 2% after APC, by 43 +/- 4% after APC + TIR, and by 46 +/- 3% after APC + TBAP. ROS generation (DHE) was increased in I/R group at 5 and 120 min reperfusion. This was attenuated by APC but this protective effect was abrogated in APC + TIR and APC + TBAP groups. CONCLUSIONS: The results indicate that ROS are central both in triggering and mediating APC, and that the mitochondrion is the target for these changes.