Effects of antioxidants on surfactant peroxidation by stimulated human polymorphonuclear leukocytes

Production of oxygen radicals by stimulated phagocytes followed by surfactant lipid peroxidation (LPO) and loss of surfactant function have all been implicated in the pathogenesis of acute lung injury. We studied the interactions between natural lung surfactant (Curosurf) and neutrophils in vitro , and compared various antioxidants; (superoxide dismutase (SOD), vitamin E, vitamin C, ebselen and melatonin), or combinations of them in duplicate and triplicate regarding their ability to decrease superoxide production and the peroxidation level of surfactant caused by activated phagocytes. The superoxide production of neutrophils activated by Candida albicans was measured with the nitroblue tetrazolium (NBT) test. The subsequent LPO was estimated as the content of malondialdehyde (MDA) and 4-hydroxyalkenals (4-HNE). We found that lung surfactant decreased the superoxide production by activated neutrophils (29.7%) and that Curosurf was peroxidized with elevated MDA/4-HNE values. With supplements of antioxidants (except vitamin C), superoxide radical production and the surfactant LPO level fell in a dose-dependent manner. The protective effect of the antioxidants differed in each test. SOD had a slight effect in both tests. The findings with vitamin E, melatonin and ebselen were similar. The best combination was that of a natural and a synthetic antioxidant (melatonin-ebselen) with a 60% decrease in comparison to the corresponding control. These findings suggest that antioxidants, particularly in combination, prevent LPO of lung surfactant.     

Effects of Antioxidants on Surfactant Peroxidation by Stimulated Human Polymorphonuclear Leukocytes

Production of oxygen radicals by stimulated phagocytes followed by surfactant lipid peroxidation (LPO) and loss of surfactant function have all been implicated in the pathogenesis of acute lung injury. We studied the interactions between natural lung surfactant (Curosurf) and neutrophils in vitro, and compared various antioxidants; (superoxide dismutase (SOD), vitamin E, vitamin C, ebselen and melatonin), or combinations of them in duplicate and triplicate regarding their ability to decrease superoxide production and the peroxidation level of surfactant caused by activated phagocytes. The superoxide production of neutrophils activated by Candida albicans was measured with the nitroblue tetrazolium (NBT) test. The subsequent LPO was estimated as the content of malondialdehyde (MDA) and 4-hydroxyalkenals (4-HNE). We found that lung surfactant decreased the superoxide production by activated neutrophils (29.7%) and that Curosurf was peroxidized with elevated MDA/4-HNE values. With supplements of antioxidants (except vitamin C), superoxide radical production and the surfactant LPO level fell in a dose-dependent manner. The protective effect of the antioxidants differed in each test. SOD had a slight effect in both tests. The findings with vitamin E, melatonin and ebselen were similar. The best combination was that of a natural and a synthetic antioxidant (melatonin-ebselen) with a 60% decrease in comparison to the corresponding control. These findings suggest that antioxidants, particularly in combination, prevent LPO of lung surfactant.     

Glutathione-deficient state of nervous tissues in starved animals intensifies lipid peroxidation and oxidation of protein SH-groups

The levels of the lipid peroxidation products (LPO), different forms of protein SH-groups and their oxidation rate in the homogenates of the mesencephalon, hypothalamus and sensorymotor cortex of normal and GSH-deficient rats under 3-day food starvation were studied. It was shown, that the basic level of LPO products--lipid hydroperoxides and malonic dialdehyde (MDA) in hypothalamus and sensorymotor cortex of normal animals are by 20-30% (p < 0.05) higher and reduced glutathione (GSH) content is 2 times higher, than these values in mesencephalon. Under 3 day starvation of normal animals activation of the LPO observed only in the hypothalamus and sensorymotor cortex, whereas under 3 day starvation of the GSH-deficient rats formed by the intraparenteraly injection of diethylmaleate in a dose of 2.5 mmol/kg of body weight in all investigated structures the lipid hydroperoxides and MDA increased many times (2-3 times), the content of the surface and masked protein SH-groups decreased and essentially increased the oxidation rate of these functional groups. It was proposed that GSH and its enzymes participate in the LPO regulation and protection of protein SH-groups from oxidative damage at this event the intensity of this prosesse depends on structural and functional organization of nervous tissues.     

乳鼠与成年大鼠晶状体中某些代谢的比较

对乳鼠与10月龄成年大鼠的晶状体代谢进行比较。结果表明,年成大鼠晶状体脂类过氧化作用较乳鼠显著高(P<0.05),而非蛋白质就基含量则较乳鼠低约22％(P<0.01),谷胱甘肽过氧化物酶(GSH-Px)活性随鼠龄增长而逐渐下降,成年大鼠GSH-Px活性较18日龄乳鼠降低62％(P<0.01),成年大鼠的谷胱甘肽还原酶活性较18日龄乳鼠低47％(P<0.01),而谷胱甘肽硫转移酶则高14％(P<0.01)。据此结果推测,去年性白内障的发生可能与晶状体抗氧化遗伤的防御机制减弱与脂类过氧化作用增加有关。而乳鼠晶状体谷胱甘肽硫转移酶(GST)活性低于成年大鼠或许是某些中毒性白内障只可在幼年动物诱发成功的影响因素之一。     

Role of bilirubin as a natural antioxidant in regulating lipid peroxidation intensity in acute viral hepatitis

Elevation of the content of lipid peroxidation (LPO) products in blood serum of patients with acute virus hepatitis (VH) is caused by an increase in the patients' blood serum lipids rather than by the intensity of peroxide reactions in lipids. There is a reverse correlation between the content of LPO products and bilirubin level and a direct correlation between lipid antioxidant activity (AOA) and bilirubin level. Marked antioxidant action of bilirubin that compares very favourably with the action of ionol (4-methyl-2,6-ditretbutylphenol) was demonstrated in the model of oxidation of methyl oleate. It was shown that the rise of lipid AOA during VH might be completely attributed to the antioxidant properties of bilirubin. It is suggested that elevation of bilirubin level and associated increase of lipid AOA during VH can be viewed as a reaction aimed at a decrease of the level of toxic products of LPO and intensification of reparative processes in the liver.     

Effect of long-term injection of high doses of potassium iodide on iodine metabolism in rat thyroid gland

Concentration of thyroid hormones in the serum of the rats after 14-day injections of potassium iodide (1, 3, 10, 100, and 500 physiological daily doses) did not differ from the control values. Excessive administration of potassium iodide increased the total iodide content in the rat thyroid tissue by 60–121% (35–108% and 94–128% for the protein-bound and free iodide, respectively), indicating the activation of the uptake and organification of iodide. The long-term injection of both low and high doses of potassium iodide increased the activity of catalase by 8–18% and SOD by 33–50% and enhanced the level of toxic LPO products reacting with thiobarbituric acid by 15–38%. It is suggested that reactive oxygen species and the excessive iodination of proteins (particularly thyroglobulin) induced by the long-term administration of high doses of potassium iodide can play an important role in the development of thyroid dysfunctions and autoimmune diseases.     

Synaptic Vesicle Proteins and Acetylcholine Levels in Chick Forebrain Nuclei Are Altered by Passive Avoidance Training

In a search for biochemical markers of modified synaptic function following training of day-old chicks on a passive avoidance task, we have assayed two monoclonal antibodies to synaptic vesicle proteins (anti-p65 and anti-SV2) and one raised to postsynaptic densities (411B). We have also measured total acetylcholine (ACh) content. Measurements were made on three forebrain regions known to show metabolic and morphological change consequent on training--the lobus parolfactorius (LPO), paleostriatum augmentatum (PA), and medial hyperstriatum ventrale (MHV)--in the right and left hemispheres 2 and 24 h after training chicks on a passive avoidance task, in which they learn to avoid pecking a bead coated with methylanthranilate [methylanthranilate-trained (M-trained)]. Control chicks were trained on a water-coated bead [water-trained (W-trained)]. Twenty-four hours after training, 411B levels showed no differences between W-trained and M-trained chicks in any region. M-training reduced the titre of anti-p65 by 16% in the left PA and 15% in the left MHV and that of anti-SV2 by 19% in the left PA. M-trained chicks showed reduced total ACh content in the LPO by up to 40% and in the PA by up to 48% but had no change in ACh level in the MHV. The decreases in antibody titre were not seen in forebrains analysed 2 h after training, but tendencies toward increases in levels in the right PA and MHV were observed with all three antibodies. Significant differences between right and left hemispheric regions, independent of training, were observed for all the antibodies and for ACh content.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparative characteristics of the antioxidant glutathione complex in the black sea molluscs Mytilus galloprovincialis Lam. and Anadara inaequivalvis Br.

The peculiarities in distribution of lipid peroxidation (LPO) products, glutathione (GSH) level, and antioxidant enzymes-glutathione peroxidase (GP) and glutathione reductase (GR)—were studied in tissues of Black Sea bivalve molluscs, Anadata inaequivalvis Br. (anadara) and Mytilus galloprovincialis Lam. (mussel, black morph), as well as their comparative characteristics were presented. The differences were established in organization of the glutathione anti-oxidant system and the LPO intensity in tissues of these mollusc species. In all anadara tissues the intensity of LPO processes was lower than that in Mytilus galloprovincialis. The GP activity in hepatopancreas and gills of mussels was significantly higher than that of anadara. On the contrary, in the foot the GP activity and GSH content in anadara considerably exceeded those in mussel. The revealed differences might reflect the peculiarities in functioning of the glutathione complex and the ratio of its activity with LPO level in tissues of anadara and mussel, as well as be of interest for understanding mechanisms of mollusc adaptation to their habitat conditions.     

Protective effects of melatonin and N-acetylserotonin on aflatoxin B1-induced lipid peroxidation in rats

Aflatoxin B1 (AFB1) is a potent hepatotoxic and hepatocarcinogenic mycotoxin. Reactive oxygen species are considered to participate in the main mechanism of aflatoxin toxicity. Melatonin (Mel) is a hormone which has antioxidative activities. N-acetylserotonin (NAc-5HT) is an immediate precursor of Mel. Melatonin is documented to be completely safe in humans and animals. The aim of our study was to examine the potential protective effects of Mel or NAc-5HT against lipid peroxidation (LPO), caused by AFB1 in male Wistar rats. Mel and NAc-5HT were intraperitoneally (i.p.) injected for 3 weeks in late afternoon (16:00-18:00) injections (20 mg kg(-1) BW/daily). AFB1 (50 microg kg(-1) BW/daily) was administered i.p. 6 h prior to indoleamine injections. Concentrations of malondialdehyde + 4-hydroxyalkenals (MDA + 4-HDA), as an index of LPO, were measured in liver, brain, lung, testis and kidney homogenates. The level of LPO in tissue homogenates was expressed as the amount of MDA + 4-HDA (nmol) per milligram of protein. AFB1 increased LPO in the liver, lung, brain and testis, but not the kidney. The increase of LPO caused by AFB1 injections was completely prevented by either Mel or NAc-5HT in all the tissues examined. Melatonin can be considered as a protective pharmacological agent in intoxication with AFB1 and the protective effect of NAc-5HT against aflatoxin-induced LPO broadens the knowledge about its antioxidative properties.     

Lipid peroxidation and the functioning of the Ca pump of the sarcoplasmic reticulum of skeletal muscle in hypercholesterolemia

During prolonged hypercholesterolemia (HCh), there was a reduction in the efficacy of Ca-pump function of the sarcoplasmic reticulum (SR) of rabbit skeletal muscles, an increase in cholesterol content, and intensification of lipid peroxidation in SR membranes. Supplementation of the cholesterol-rich diet with alpha-tocopherol effectively prevented dysfunction of the SR Ca-pump and reduced the enhanced LPO level in SR membranes without having any effect on cholesterol content in blood serum and SR membranes. The increase in the LPO level seems likely to be primarily responsible for abnormalities in the SR Ca-pump during HCh.     

Estrogen Hormones Reduce Lipid Peroxidation in Cells and Tissues of the Central Nervous System

Effects of estrogen hormones on lipid peroxidation (LPO) were examined in rat brain homogenates (RBHs), hippocampal HT 22 cells, rat primary neocortical cultures, and human brain homogenates (HBHs). Dose-response curves indicated half-maximal effective concentrations (EC50) of 5.5 and 5.6 mM for iron-induced LPO in RBHs and HT 22 homogenates. Incubation of living rat primary neocortical cultures with iron resulted in an EC50 of 0.5 mM, whereas culture homogenates showed an EC50 of 1.2 mM. Estrogen hormones reduced LPO in all systems: In RBHs, estrone inhibited iron-induced LPO to 74.1 +/- 5.8% of control levels (17beta-estradiol: 71.3 +/- 0.1%) at a concentration of 10 microM. In hippocampal HT 22 cell homogenates, levels of LPO were reduced to 74.8 +/- 5.5% by estrone and to 47.8 +/- 6.2% by 17beta-estradiol. In living neocortical cultures, 17beta-estradiol decreased iron-induced LPO to 79.2 +/- 4.8% and increased the survival of cultured neuronal cells. Of the other steroid compounds tested (corticosterone, progesterone, testosterone), only progesterone decreased LPO in HT 22 cell homogenates. In HBHs, LPO was dose-dependently increased by iron concentrations from 2.7 to 6.0 mM. Incubation with estrogens resulted in a dose-dependent inhibition of LPO to 53.8 +/- 8.6% with 10 microM 17beta-estradiol, whereas estrone failed to affect iron-induced LPO to a significant extent. Nonestrogenic steroids, including hydrocortisol, did not show significant effects on LPO in HBHs.     

Effects of temperature and dietary protein level on hepatic oxidative status of Senegalese sole juveniles (Solea senegalensis)

Effects of 55 and 45% dietary protein levels (55P and 45P diets, respectively) and temperature (12 and 18°C) on hepatic activity of superoxide dismutase (SOD), catalase, glutathione peroxidase, glutathione reductase (GR), glucose-6-phosphate dehydrogenase and lipid peroxidation (LPO) levels of Solea senegalensis juveniles were studied. Further, effects of acute thermal shocks provoked by a drop (18°C to 12°C) or a rise (12°C to 18°C) of water temperature on sole oxidative state was also evaluated. Dietary protein reduction increased LPO levels though no major alterations were found on antioxidant enzyme activities between dietary treatments. At 12°C GR activity was higher and SOD activity was lower than 18°C but LPO levels were not affected. In both thermal shock cases, LPO levels increased in 55P group, probably due to insufficient antioxidant enzyme activation. In contrast, fish of 45P group under acute exposition to warmer and colder temperature exhibited no substantial changes and a significant decrease on LPO levels, respectively, along with no major changes in antioxidant enzymes. Overall, results suggest that independently of rearing temperatures 45P group was more susceptible to oxidative stress than 55P group. Thermal shock either due to rise or drop of temperature seemed to induce oxidative stress in 55P group.     

Biphasic dependence of some ecomorphological and biochemical parameters of the birch leaf plate on the level of motor traffic pollution

The dependence of photosynthetic pigment (PP) content, lipid peroxidation (LPO) rate, and fluctuating asymmetry (FA) of the leaf plate on the level of motor traffic pollution has been studied in the drooping birch (Betula pendula Roth.). It has been shown that this dependence has a biphasic pattern. At the first phase, an increase in pollution pressure leads to disturbances in the homeostasis of trees manifested in reduction of PP content, intensification of LPO, and increase in the FA index. At the second phase, further increase in pollution pressure has an opposite effect, normalizing homeostasis (LPO rate and FA index decrease, while PP content increases).     

The adaptational changes in lipid peroxidation under the chronic action of an electrostatic field

Experiments on young puberal Wistar rats have shown that chronic effect of the electrostatic field brings lipid peroxidation (LPO) to a new level of the dynamic equilibrium. Metabolism of lipids proved to be sensitive to this factor. But the systems regulating LPO actively holds a new equilibrium state. Inert LPO products of the lipopigments type can bind vitamin E whose content in tissues remains unchanged.     

Lipid peroxidation as molecular mechanism of liver cell injury during reperfusion after ischemia

The pathophysiological importance of reactive oxygen species has been extensively documented in the pathogenesis of hepatic ischema-reperfusion injury. Kupffer cells and neutrophils were identified as the dominant sources of the postischemic oxidant stress. To test the hypothesis that a direct free radical-mediated injury mechanism (lipid peroxidation; LPO) may be involved in the pathogenesis, highly sensitive and specific parameters of LPO, i.e., hydroxy-eicosatetraenoic acids (HETES), and F₂-isoprostanes, were determined by gas chromatographic-mass spectrometric analysis in liver tissue and plasma during 45 min of hepatic ischemia and up to 24 h of reperfusion. A significant 60–250% increase of F₂-isoprostane levels in plasma was found at all times during reperfusion; the HETE content increased only significantly at 1 h of reperfusion and in severely necrotic liver tissue at 24 h with increases between 90–320%. On the other hand, in a model of LPO-induced liver injury (infusion of 0.8 μmol tert-butylhydroperoxide/min/g liver), the hepatic HETE content increased two to fourfold over baseline values at 45 min, i.e., before liver injury. A further increase to 12- to 30-fold of baseline was observed during moderate liver injury. Based on these quantitative comparisons of LPO and liver injury, it seems highly unlikely that LPO is the primary mechanism of parenchymal cell injury during reperfusion, although it cannot be excluded that LPO may be important as a damaging mechanism in a limited compartment of the liver, e.g., endothelial cells, close to the sources of reactive oxygen, e.g., Kupffer cells and neutrophils.     

Endothelial cell fatty acid unsaturation mediates cold-induced oxidative stress

Ultraprofound hypothermia (< 5 degrees C) induces changes to cell membranes such as liquid-to-gel lipid transitions and oxidative stress that have a negative effect on membrane function and cell survival. We hypothesized that fatty acid substitution of endothelial cell lipids and alterations in their unsaturation would modify cell survival at 0 degrees C, a temperature commonly used during storage and transportation of isolated cells or tissues and organs used in transplantation. Confluent bovine aortic endothelial cells were treated with 18-carbon fatty acids (C18:0, C18:1n-9, C18:2n-6, or C18:3n-3), C20:5n-3 or C22:6n-3 (DHA), and then stored at 0 degrees C without fatty acid supplements. Storage of control cells caused the release of lactate dehydrogenase (LDH) and a threefold increase in lipid peroxidation (LPO) when compared to control cells not exposed to cold. Pre-treating cells with C18:0 decreased the unsaturation of cell lipids and reduced LDH release at 0 degrees C by 50%, but all mono- or poly-unsaturated fatty acids increased injury in a concentration-dependent manner and as the extent of fatty acid unsaturation increased. DHA-treatment increased cell fatty acid unsaturation and caused maximal injury at 0 degrees C, which was prevented by lipophilic antioxidants BHT or vitamin E, the iron chelator deferoxamine, and to a lesser extent by vitamin C. Furthermore, the cold-induced increase in LPO was reduced by C18:0, vitamin E, or DFO but enhanced by DHA. In conclusion, the findings implicate iron catalyzed free radicals and LPO as a predominant mechanism of endothelial cell injury at 0 degrees C, which may be reduced by increasing lipid saturation or treating cells with antioxidants.     

Modification of cardiac oxidative stress in alloxan-induced diabetic rabbits with repaglinide treatment

The aim of this study was to analyze the antioxidative effect of repaglinide in the heart of alloxan-induced diabetic rabbits. The activities of superoxide dismutase (Cu,Zn-SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GSSG-R), glutathione (GSH), ascorbic acid (AA), products of lipid peroxidation (LPO) and protein carbonyl groups (PCG) were estimated after 4 and 8 weeks of repaglinide treatment (1 mg daily). At significance level p<0.05, in diabetic heart the activities of Cu,Zn-SOD and CAT were elevated as compared to control values (by 60.7% and 55.3% for Cu,Zn-SOD, and by 89.7% and 77.4% for CAT after 4 and 8 weeks, respectively). The level of AA was diminished by 52.5% and 41.5% while GSH-Px and GSSG-R activities were decreased after 4 weeks of experiment (by 11.5% and 14.4%, respectively). GSH level was diminished by 33.2% after 8 weeks. Simultaneously, in diabetic heart the levels of LPO and PCG were elevated as compared to control values (by 51.6% and 111.3% for LPO, and by 72.0% and 132.9% for PCG after 4 and 8 weeks, respectively). In diabetic animals, repaglinide normalized GSH-Px activity and GSH level. It modified the activities of Cu,Zn-SOD, CAT and AA as compared to diabetic non-treated animals. In diabetic-treated rabbits the level of LPO was diminished as compared to diabetic non-treated animals, while the level of PCG was not affected. In the present study, repaglinide did not affect blood glucose and plasma insulin concentrations in diabetic rabbits. Nevertheless, the drug showed some beneficial antioxidative properties in the heart tissue.     

Heme oxygenase activity in rat organs during cadmium chloride administration

Heme oxygenase activity, the level of spontaneous and ascorbat-induced LPO in the liver, kidney and spleen homogenates of rats and blood serum absorption spectrum in the Soret region in different periods both after CdCl2 and prior alpha-tocopherol administration were studied. The increase in the hemolysis products content in the serum was observed in 15 min after CdCl2 injection and remained during 24 h. Heme oxygenase activity in the liver and kidney increased after 6 h and stayed at the same level 24 h after CdCl2 administration. The level of spontaneous LPO in the spleen increased after 6 h, and in the liver and kidney the level of spontaneous and ascorbat-induced LPO increased in 24 h after CdCl2 injection. The preliminary alpha-tocopherol administration did not prevent the accumulation of hemolysis products in the serum and the increase of heme oxygenase activity in the liver and kidney caused by CdCl2 administration. However, the increase in the ascorbat-induced LPO in these organs was completely blocked. The role of heme and LPO in the heme oxygenase induction by CdCl2 are discussed.     

邻苯二甲酸二丁酯对翡翠贻贝抗氧化酶及脂质过氧化水平的影响

实验室条件下,研究了不同浓度邻苯二甲酸二丁酯(DBP)长期胁迫(15 d)对翡翠贻贝内脏团和外套膜抗氧化酶(超氧化物歧化酶SOD、过氧化氢酶CAT)及脂质过氧化(LPO)水平(以MDA含量表示)的影响,以及受胁迫翡翠贻贝在清洁海水中恢复阶段上述生化指标的变化特征.结果表明:胁迫阶段,0.5和2.5 mg.L-1DBP下翡翠贻贝内脏团SOD活性表现为先抑制后逐渐恢复,12.5和62.5 mg.L-1下则持续受到显著抑制;不同浓度组CAT活性均明显被抑制.LPO水平明显升高.外套膜中,2.5 mg.L-1下SOD活性受到持续诱导,其他浓度组则先被抑制,后随曝露时间延长逐渐被诱导;各浓度组CAT的变化波动较大,没有明显规律;而LPO水平明显升高.净化恢复阶段,12.5和62.5 mg.L-1DBP胁迫下的内脏团SOD和CAT活性恢复较慢,其LPO水平随时间延长逐渐恢复至对照组水平;外套膜中SOD活性呈持续升高趋势,CAT活性和LPO水平则随时间延长恢复到对照组水平.     

三硝基甲苯中毒性白内障动物模型的建立及其发病机理的初步研究

反复多次给大鼠皮下注射20％三硝基甲苯(TNT)甘油:水混悬液,染毒15个月后21％动物发生白内障,其裂隙灯检查结果与人TNT性白内障基本相似,同时注射甘油:水溶剂的对照组大鼠无一例发生白内障。染毒10个月的大鼠,其晶状体LPO增高,GSH-P_X及GST活性降低,GR活性无变化,而GSH含量明显增加;注射TNT后肝脏LPO值、GSH含量、GSH-P_X、GR及GST活性均明显增高。本文结果提示,TNT中毒性白内障的形成可能系TNT及其代谢产物直接作用于晶状体,造成昌状体氧化损伤所致。TNT白内障大鼠模型的建立亦为深入探讨其发病机理及防治奠定了基础。