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1.
The effect of nine dibenzo[a,c]cyclooctene lignans isolated from Fructus schizandrae on in vitro and in vivo lipid peroxidation of liver microsomes as well as on anti-oxidative enzyme activities were studied. Seven of the nine lignans (1 mM) were shown to inhibit Vit C/NADPH induced lipid peroxidation (malondialdehyde (MDA) formation) of rat liver microsomes. Of these compounds, schisanhenol (Sal), S(-)schizandrin C (S(-)sin C) and S(-)schizandrin B (S(-)sin B) were shown to be more potent than Vit E at the same concentration. Sal and Sin B were able to inhibit gossypol-induced superoxide anion generation in rat liver microsomes. In addition, oral administration of Sal and Sin B markedly reduced liver MDA formation induced by ethanol, 15 ml/kg in mice, and increased superoxide dismutase and catalase activities in rat liver cytosol. The data of this paper are in favor of the conclusion that some lignans, like Sal, have strong anti-oxidant activity. The mechanisms of anti-oxidant activity of the lignans were discussed.  相似文献   

2.
Feng Y  Lu Y  Lin X  Gao Y  Zhao Q  Li W  Wang R 《Life sciences》2008,82(13-14):752-763
The protection of brain mitochondria from oxidative stress is an important therapeutic strategy against ischemia-reperfusion injury and neurodegenerative disorders. Isolated brain mitochondria subjected to a 5 min period of anoxia followed by 5 min reoxygenation mirrored the effect of oxidative stress in the brain. The present study attempts to evaluate the protective effects of endomorphin 1 (EM1), endomorphin 2 (EM2), and morphine (Mor) in an in vitro mouse brain mitochondria anoxia-reoxygenation model. Endomorphins (EM1/2) and Mor were added to mitochondria prior to anoxia or reoxygenation. EM1/2 and Mor markedly improved mitochondrial respiratory activity with a decrease in state 4 and increases in state 3, respiratory control ratio (RCR) and the oxidative phosphorylation efficiency (ADP/O ratio), suggesting that they may play a protective role in mitochondria. These drugs inhibited alterations in mitochondrial membrane fluidity, lipoperoxidation, and cardiolipin (CL) release, which indicates protection of the mitochondrial membranes from oxidative damage. The protective effects of these drugs were concentration-dependent. Furthermore, these drugs blocked the enhanced release of cytochrome c (Cyt c), and consequently inhibited the cell apoptosis induced by the release of Cyt c. Our results suggest that EM1/2 and Mor effectively protect brain mitochondria against oxidative stresses induced by in vitro anoxia-reoxygenation and may play an important role in the prevention of deleterious effects during brain ischemia-reperfusion and neurodegenerative diseases.  相似文献   

3.
支链氨基酸对心肌缺血大鼠线粒体损伤的保护作用   总被引:1,自引:0,他引:1  
目的和方法:本文用异丙肾上腺素(Iso) 造成大鼠心肌缺血动物模型,观察支链氨基酸(BCAA)对大鼠心肌缺血时线粒体结构和功能损伤的预防作用。结果:BCAA 能显著降低心肌缺血后心肌线粒体中丙二醛(MDA) 水平、维持线粒体模平均微粘度(-η) 、线粒体呼吸链中细胞色素氧化酶及心肌肌球蛋白ATPase活力。结论:给予BCAA对保护大鼠心肌线粒体的结构和功能免受缺血性损伤具有一定效果  相似文献   

4.
The purpose of this work was to evaluate the response of the antioxidant system of goldfish Carassius auratus during anoxia and reoxygenation. The exposure of goldfish to 8 h of anoxia induced a 14% decrease in total glutathione levels in the kidney, although the liver, brain, and muscle were unaffected. Anoxia also resulted in increases in the activities of liver catalase, brain glucose-6-phosphate dehydrogenase, and brain glutathione peroxidase (by 38, 26, and 79%, respectively) and a decrease in kidney catalase activity (by 17.5%). After 14 h of reoxygenation, liver catalase and brain glutathione peroxidase activities remained higher than controls and several other tissue-specific changes occurred in enzyme activities. Superoxide dismutase activity was unaffected by anoxia and reoxygenation. The levels of conjugated dienes, as indicators of lipid peroxidation, increased by 114% in liver after 1 h of reoxygenation and by 75% in brain after 14 h of reoxygenation. Lipid peroxidation was unaffected in kidney and depressed during anoxia and reoxygenation (by 44-61%) in muscle. Regulation of the goldfish antioxidant system during anoxia may constitute a biochemical mechanism that minimizes oxidative stress following reoxygenation.  相似文献   

5.
酸枣仁总皂甙对缺氧-再给氧心肌细胞的保护作用   总被引:1,自引:0,他引:1  
按Laarse's方法建立培养心肌细胞缺氧-再给氧(A-R)模型,缺糖缺氧60min,再给氧30min.结果发现,缺氧组心肌细胞MDA含量增加,SOD活性降低,细胞膜脂质流动性下降,再给氧组上述改变加剧.酸枣仁总皂忒(ZS)能剂量依赖性地显著降低心肌细胞MDA含量,提高SOD活性,增加细胞膜脂质流动性,证明ZS有明显抗心肌细胞缺氧-再给氧损伤作用.  相似文献   

6.
The present study investigated the protective effects of Ginkgo biloba extract (EGb 761) on rat liver mitochondrial damage induced by in vitro anoxia/reoxygenation. Anoxia/reoxygenation was known to impair respiratory activities and mitochondrial oxidative phosphorylation efficiency. ADP/O (2.57 +/- 0.11) decreased after anoxia/reoxygenation (1.75 +/- 0.09, p < .01), as well as state 3 and uncoupled respiration (-20%, p < .01), but state 4 respiration increased (p < .01). EGb 761 (50-200 microg/ml) had no effect on mitochondrial functions before anoxia, but had a specific dose-dependent protective effect after anoxia/reoxygenation. When mitochondria were incubated with 200 microg/ml EGb 761, they showed an increase in ADP/O (2.09 +/- 0.14, p < .05) and a decrease in state 4 respiration (-22%) after anoxia/reoxygenation. In EPR spin-trapping measurement, EGb 761 decreased the EPR signal of superoxide anion produced during reoxygenation. In conclusion, EGb 761 specially protects mitochondrial ATP synthesis against anoxia/reoxygenation injury by scavenging the superoxide anion generated by mitochondria.  相似文献   

7.
Rat brain mitochondria were successively submitted to anoxia and reoxygenation. The main mitochondrial functions were assessed at different reoxygenation times. Although the respiratory control ratio decreased, the activity for each one of the enzymes participating in the respiratory chain was not affected. However, during reoxygenation, mitochondrial membrane lipoperoxidation quickly increased and was proportional to the decrease seen in membrane fluidity. Under the same conditions, cytochrome c and cardiolipin were released from mitochondria and their rate of release increased with reoxygenation time. The release of cytochrome c and cardiolipin was followed by the collapse of the membrane potential and it was not inhibited by cyclosporin A. Addition of the antioxidant alpha-tocopherol abolished all these reoxygenation-induced changes. These data indicate that, in this model, reoxygenation promotes the uncoupling of respiratory chain, and cytochrome c and cardiolipin releases. These events are not related to the membrane potential collapse but to an oxidative stress.  相似文献   

8.
Mitochondrial dysfunction in ischemic liver has been demonstrated to be due to decrease in the intramitochondrial level of ATP and the subsequent disruption of the proton barrier of the inner membrane (Watanabe, F., Hashimoto, T. and Tagawa, K. (1985) J. Biochem. 97, 1229-1234). In this study, another injury process, impairment of the electron-transfer system, which occurred during reoxygenation of ischemic liver, was studied during reperfusion of cold preserved liver and during cold incubation of isolated rat-liver mitochondria. The sites of the respiratory chain that were sensitive to peroxidative damage were ubiquinone-cytochrome c oxidoreductase and NADH-ubiquinone oxidoreductase. These enzymic activities decreased with increase in lipid peroxidation. Incubation of submitochondrial particles with t-butyl hydroperoxide or with an NADPH-dependent peroxidation system decreased the enzymic activities of the electron-transport system. These data strongly suggested that lipid peroxidation during reoxygenation of ischemic liver impaired the electron-transfer system. Thus, mitochondria of ischemic liver suffer from two different types of injury: increase in proton permeability during anoxia, and decrease in enzymic activities of the electron-transport system during reoxygenation.  相似文献   

9.
离体大鼠心肌细胞钠超负荷与缺氧—复氧损伤   总被引:6,自引:0,他引:6  
李兆萍  唐朝枢 《生理学报》1989,41(3):304-307
本工作在离体成年大鼠心肌细胞缺氧-复氧模型上,观察到细胞无氧孵育时加入Na~ -K~ ATP酶抑制剂哇巴因,增加细胞内钠离子浓度,复氧孵育后造成了更严重的细胞损伤及钙超负荷,缺氧期末细胞内钠离子浓度与复氧后钙超负荷的程度呈显著正相关。复氧期给予Na~ -Ca~(2 )交换抑制剂Mn~(2 ),明显减轻了细胞的缺氧-复氧损伤,Mn~(2 )还显著抑制了无钠孵育引起的细胞损伤。结果提示:缺氧期细胞内钠超负荷是复氧时细胞内钙超负荷发生的条件,Na~ -Ca~(2 )交换是Ca~(2 )进入细胞的重要途径。  相似文献   

10.
Oxidative stress induced by Fe2+ (50 microM) and ascorbate (2 mM) in isolated rat brain mitochondria incubated in vitro leads to an enhanced lipid peroxidation, cardiolipin loss and an increased formation of protein carbonyls. These changes are associated with a loss of mitochondrial membrane potential (depolarization) and an impaired activity of electron transport chain (ETC) as measured by MTT reduction assay. Butylated hydroxytoluene (0.2 mM), an inhibitor of lipid peroxidation, can prevent significantly the loss of cardiolipin, the increased protein carbonyl formation and the decrease in mitochondrial membrane potential induced by Fe2+ and ascorbate, implying that the changes are secondary to membrane lipid peroxidation. However, iron-ascorbate induced impairment of mitochondrial ETC activity is apparently independent of lipid peroxidation process. The structural and functional derangement of mitochondria induced by oxidative stress as reported here may have implications in neuronal damage associated with brain aging and neurodegenerative disorders.  相似文献   

11.
A noticeable loss of cardiolipin, a significant accumulation of fluorescent products of lipid peroxidation and an increased ability to produce reactive oxygen species in vitro are characteristics of aged rat brain mitochondria, as has been demonstrated in this study. In contrast mitochondrial electron transport chain activity is not significantly compromised except a marginal decline in complex IV activity in aged rat brain. On the other hand, a striking loss of mitochondrial membrane potential occurs in brain mitochondria during aging, which may be attributed to peroxidative membrane damage in this condition. Such mitochondrial dysfunctions as reported here may lead to uncoupling of oxidative phosphorylation, ATP depletion and activation of apoptotic cascade in aged rat brain.  相似文献   

12.
Han J  Kim N  Park J  Seog DH  Joo H  Kim E 《Journal of biochemistry》2002,131(5):721-727
The purpose of this study was to determine whether ATP-sensitive potassium channel (K(ATP) channel) activation generates oxygen free radicals in the rabbit heart. We assayed malondialdehyde (MDA) in rabbit heart slices in vitro as an indicator of oxygen free radical generation. The K(ATP) channel openers, pinacidil and cromakalim, significantly increased MDA production in a concentration-dependent manner. MDA formation also increased linearly with incubation time in the presence of K(ATP) channel openers. The K(ATP) channel blockers, glibenclamide and 5-hydroxydecanoate (5-HD), decreased K(ATP) channel opener-induced MDA formation in a concentration-dependent manner. When Fe(2+) was administered to heart slices that had been pretreated with K(ATP) channel openers, a marked elevation in MDA was observed, compared to heart slices that were treated with Fe(2+) alone. A positive linear correlation between Fe(2+) and MDA level was observed. The MDA levels of heart slices subjected to anoxia for 15 min remained unchanged until reperfusion. When the heart slices were reoxygenated for 30 min, a marked increase in MDA formation was observed. However, in the presence of glibenclamide and 5-HD, reperfusion following anoxia did not result in increased MDA. These results suggest that the opening of mitochondrial K(ATP) channels in rabbit heart slices evokes oxygen free radical generation via a Fenton-type reaction.  相似文献   

13.
The mechanism of Cr(VI)-induced toxicity in plants and animals has been assessed for mitochondrial bioenergetics and membrane damage in turnip root and rat liver mitochondria. By using succinate as the respiratory substrate, ADP/O and respiratory control ratio (RCR) were depressed as a function of Cr(VI) concentration. State 3 and uncoupled respiration were also depressed by Cr(VI). Rat mitochondria revealed a higher sensitivity to Cr(VI), as compared to turnip mitochondria. Rat mitochondrial state 4 respiration rate triplicated in contrast to negligible stimulation of turnip state 4 respiration. Chromium(VI) inhibited the activity of the NADH-ubiquinone oxidoreductase (complex I) from rat liver mitochondria and succinate-dehydrogenases (complex II) from plant and animal mitochondria. In rat liver mitochondria, complex I was more sensitive to Cr(VI) than complex II. The activity of cytochrome c oxidase (complex IV) was not sensitive to Cr(VI). Unique for plant mitochondria, exogenous NADH uncoupled respiration was unaffected by Cr(VI), indicating that the NADH dehydrogenase of the outer leaflet of the plant inner membrane, in addition to complexes III and IV, were insensitive to Cr(VI). The ATPase activity (complex V) was stimulated in rat liver mitochondria, but inhibited in turnip root mitochondria. In both, turnip and rat mitochondria, Cr(VI) depressed mitochondrial succinate-dependent transmembrane potential (Deltapsi) and phosphorylation efficiency, but it neither affected mitochondrial membrane permeabilization to protons (H+) nor induced membrane lipid peroxidation. However, Cr(VI) induced mitochondrial membrane permeabilization to K+, an effect that was more pronounced in turnip root than in rat liver mitochondria. In conclusion, Cr(VI)-induced perturbations of mitochondrial bioenergetics compromises energy-dependent biochemical processes and, therefore, may contribute to the basal mechanism underlying its toxic effects in plant and animal cells.  相似文献   

14.
Adenosine diphosphatase (ADPase) activity was studied in rat liver with [beta-32P]ADP as a substrate. Mitochondria and outer mitochondrial membrane fractions were isolated and assayed for ADPase and various marker enzymes. ADPase activity was strikingly reduced when the outer membranes were removed from the mitochondria whether by digitonin treatment or osmotic shock. Addition of the inter-membrane space subfraction to the purified outer membranes resulted in enhanced ADPase activity. Addition of the inter-mitochondrial membrane enzyme adenylate kinase to outer membranes also produced a large stimulation of activity. The ADPase activity could also be reconstituted in vitro with adenylate kinase and either mitoplast ATPase or ouabain-sensitive (Na+ + K+ + Mg2+)-ATPase. Chloroform-released ATPase, however, was not capable of producing an ADPase activity when combined with adenylate kinase. Gel permeation chromatography of Triton-solubilised outer mitochondrial membranes was unable to resolve ADPase activity from contaminating ATPase. These results suggest that the majority of ADPase activity in rat liver mitochondria consists of the coupled activity of adenylate kinase and ATPase.  相似文献   

15.
莱氏衣原体膜上Mg~(2+)-ATPase用DOC溶解后,经Sepharose-6B和DEAE-CelluloseDE-52离子交换柱,得到了部分纯化的Mg~(2+)ATPase,并将此ATPase与不同极性头部的磷脂和膜糖脂重组,研究了不同的极性头部的磷脂和膜糖脂对ATPase活性的影响。此酶的活性不依赖酸性磷脂,PG、DPG、大豆磷脂等明显抑制酶活性,中性磷脂DMPC、PE、PC则能增加酶活性,其中尤以非双层脂PE的作用最为明显。从莱氏衣原体膜上提取的糖脂(MGDG,DGDG)单独和ATPase重组时,酶活性增加并不明显,当MGDG和DGDG以等比例混合时,能大大地增加酶活性。这表明Mg~(2+)-ATPase的活性很大程度上与磷脂的表面电荷及磷脂的组成相关。  相似文献   

16.
A method is described for the preparation of ;free' and ;synaptosomal' brain mitochondria from fractions of guinea-pig cerebral cortex respectively depleted and enriched in synaptosomes. Both preparations of mitochondria have a low membrane H(+) conductance, a high capacity to phosphorylate ADP, and a capacity to accumulate Ca(2+) at rates limited by the activity of the respiratory chain. Ca(2+) transport by ;free' brain mitochondria is compared with that of heart mitochondria. The Ca(2+) conductance of ;free' brain mitochondria was at least 20 times that for rat heart mitochondria. Ca(2+) uptake by brain mitochondria increased the pH gradient and decreased membrane potential, whereas little change occurred during the much slower uptake by heart mitochondria. In the presence of ionophore A23187, dissipative Ca(2+) cycling decreased the H(+) electrochemical potential gradient of brain mitochondria from 190 to 60mV, but caused only a slight decrease with heart mitochondria, although the ionophore lowered the pH gradient and increased membrane potential. The Ca(2+) conductance of ;free' brain mitochondria is distinctive in showing a hyperbolic dependency on free Ca(2+) concentration. In the presence of Ruthenium Red, a rapid Na(+)-dependent Ca(2+) efflux occurs. The H(+) electrochemical potential gradient is maintained during this efflux, and membrane potential increases, with both ;free' brain and heart mitochondria. The Na(+) requirement for Ca(2+) efflux appears not to be related to the high Na(+)/H(+) exchange activity but may represent a direct exchange of Na(+) for Ca(2+).  相似文献   

17.
The aim of the study was to investigate the effect of in vitro anoxia/reoxygenation on the oxidative phosphorylation of isolated lung mitochondria. Mitochondria were isolated after harvesting from fresh pig lungs flushed with Euro-Collins solution. Mitochondrial respiratory parameters were determined in isolated mitochondria before anoxia (control), after 5-45 min anoxia followed by 5 min reoxygenation, and after 25 or 40 min of in vitro incubation in order to follow the in vitro aging of mitochondria during respiratory assays. Respiratory parameters measured after anoxia/reoxygenation did not show any oxidative phosphorylation dysfunction, indicating a high resistance of pulmonary mitochondria to in vitro anoxia/reoxygenation (up to 45 min anoxia). These results indicate that mitochondria are not directly responsible of their oxidative phosphorylation damage observed after in vivo ischemia (K. Willet et al., Transplantation 69 (2000) 582) but are a target of others cellular injuries leading to mitochondrial dysfunction in vivo.  相似文献   

18.
Freshwater turtles survive prolonged anoxia and reoxygenation without overt brain damage by well-described physiological processes, but little work has been done to investigate the molecular changes associated with anoxic survival. We examined stress proteins and apoptotic regulators in the turtle during early (1 h) and long-term anoxia (4, 24 h) and reoxygenation. Western blot analyses showed changes within the first hour of anoxia; multiple stress proteins (Hsp72, Grp94, Hsp60, Hsp27, and HO-1) increased while apoptotic regulators (Bcl-2 and Bax) decreased. Levels of the ER stress protein Grp78 were unchanged. Stress proteins remained elevated in long-term anoxia while the Bcl-2/Bax ratio was unaltered. No changes in cleaved caspase 3 levels were observed during anoxia while apoptosis inducing factor increased significantly. Furthermore, we found no evidence for the anoxic translocation of Bax from the cytosol to mitochondria, nor movement of apoptosis inducing factor between the mitochondria and nucleus. Reoxygenation did not lead to further increases in stress proteins or apoptotic regulators except for HO-1. The apparent protection against cell damage was corroborated with immunohistochemistry, which indicated no overt damage in the turtle brain subjected to anoxia and reoxygenation. The results suggest that molecular adaptations enhance pro-survival mechanisms and suppress apoptotic pathways to confer anoxia tolerance in freshwater turtles.  相似文献   

19.
目的:观察非选择性一氧化氮合酶抑制剂NG-硝基-L-精氨酸(NG-nitro-L-arginine,L-NA)对局灶性脑缺血大鼠脑线粒体的损伤作用,以探讨其改善缺血性脑损伤的作用机制。方法:将大鼠随机分为假手术组、缺血对照组、L-NA治疗组,采用线栓法阻断大鼠大脑中动脉(MCAO)复制局灶性脑缺血模型,分别于缺血后2h、6h、12h给药治疗3d,迅速断头取脑,差速离心法提取缺血侧脑组织线粒休,迅速测定线粒体膜肿胀度及线粒体活力,测定线粒体总ATP酶、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性,以及线粒休一氧化氮(NO)、丙二醛(MDA)含量:电镜观察缺血后皮层神经元超微结构的改变及L-NA对其影响。结果:在大鼠MCAO后线粒体膜肿胀度增加,线粒体活力下降,线粒体NO、MDA含量明显增加,线粒体总ATP酶、SOD、GSH-Px活性均明显下降:缺血后2h、6h、12h给予L-NA治疗3d与缺血对照组相比NO含量明显下降,缺血后12h治疗组线粒体膜肿胀度、线粒体活力、总ATP酶、SOD、GSH-Px活性均显著升高、MDA含量下降。电镜结果显示脑缺血后皮层神经元水肿,线粒体肿胀、嵴断裂、溶解、消失,且随缺血时间延长损伤加重;缺血后12h给予L-NA治疗能明显改善脑缺血引起的神经元水肿、线粒体肿胀和空泡化。结论:L-NA能明显抑制脑缺血后线粒体NO生成,在缺血早期给予L-NA对缺血性脑损伤无改善作用:缺血后期给予L-NA,能明显降低线粒体膜肿胀程度,改善线粒体能量供应,增强线粒体抗氧化作用及其活力,从而减轻脑缺血损伤。  相似文献   

20.
Incubation of sheep platelet crude membranes with xanthine oxidase (XO)/hypoxanthine/Fe(2+)-ADP revealed: (i) a fast peroxidative response - with a maximal linear rate of 14 nmol malondialdehyde (MDA) equivalents/mg protein, as evidenced by the thiobarbituric acid test - and a decrease in the polyunsaturated fatty acid (PUFA) content of the platelet crude membranes; (ii) a decrease in the lipid fluidity in the deep lipid core of the membranes but not at the membrane surface; (iii) a dramatic inhibitory effect on glucose 6-phosphatase (Glc-6-Pase) but not on acetylcholinesterase activity. Platelets were also aged by storage at 4 degrees C in their own plasma or in Seto additive solution. In these media, platelet aggregates were visible and the effects on platelet phospholipids, PUFA, lipid extract fluorescence, crude membrane fluidity and membrane-bound enzyme activities were assessed for comparison with those observed in in vitro lipid peroxidation. The sensitivity of membranes from stored platelets to lipid peroxidation was also assessed. Storage of platelets in plasma for 5 days was associated with different changes in their crude membranes such as decreases in arachidonic acid contents, the decrease not being avoided by the presence of phospholipase A(2) inhibitors, increases in MDA equivalents, conjugated dienes and lipid extract fluorescence, decreases in the amounts of MDA equivalents formed by platelet crude membranes treated with the oxidizing agents, changes in membrane fluidity and inhibition of Glc-6-Pase. All these alterations were less pronounced or even abolished after platelet storage in Seto. These findings suggest that platelet lipid peroxidation due to XO/hypoxanthine/Fe(2+)-ADP and platelet membrane alterations observed after platelet ageing under storage at 4 degrees C share common features. Also, as regards the prevention of peroxidative processes, Seto solution permits better storage of sheep platelets than plasma.  相似文献   

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