Effect of vitamin E supplementation on lipid peroxidation in blood and lung of influenza virus infected mice

The influenza virus infection (A/Aichi/2/68) was associated with development of oxidative stress in lung and blood of mice, accompanied by an increase in levels of lipid peroxidation products (conjugated dienes and total malondialdehyde) and a decrease in endogenous amounts of natural antioxidant vitamin E. These effects were most pronounced on the 5th day after virus inoculation, in comparison with those on the 7th. Supplementation of mice with exogenous vitamin E before virus inoculation lead to lung and blood protection against lipid peroxidation. A marked decrease in lipid peroxidation products and an increase in vitamin E content was established in blood and lung on the 5th and 7th day after virus inoculation. The stabilizing effect of vitamin E is dose-dependent in blood and dose-independent in lung, and was most pronounced on the 5th day after virus inoculation in comparison with the 7th day.

Pharmacodynamic of the antioxidant action of alpha-tocopherol and its derivatives in liver, brain, heart and skeletal muscles

The aim of the present work was to determine the pharmacodynamics of antioxidant effect of alpha-tocopherol and its derivatives (alpha-tocopheryl esters and chromanols with different chain-length) in the animal tissues, as well as the role of cytochrome P-450 in biotransformation of these compounds. Alpha-tocopherol and its derivatives were injected intraperitoneally in rats or mice in a single dose of 100 mmol per kg b.w. The animals were sacrificed at different time intervals (0, 1, 2, 4, 8, 12, 24, 36 hours) and the liver, heart, brain and skeletal muscles were removed, homogenized and incubated with lipid peroxidation (LPO) inducers (Fe2+ + ascorbate). LPO was evidenced by the generated malone dialdehyde (MDA). Data were expressed as percentage of LPO inhibition by alpha-tocopherol or its derivatives as compared to control group. The kinetic curves of the inhibitory action of alpha-tocopherol and its derivatives on LPO were characterized by three phases: a phase of increasing antioxidant activity, a phase of maximal antioxidant activity (about 60-95% LPO inhibition), and a phase of decreasing antioxidant activity. Alpha-tocopheryl esters possessed dynamics of antioxidant action the same as alpha-tocopherol. Therefore the hydrolysis of alpha-tocopheryl esters in animal organism is not a limiting factor for their antioxidant effect. The alpha-tocopherol derivatives with short chain-length (C1, C6) had a shorter half-life in animal tissues as compared to alpha-tocopherol or its esters. In vitro experiments showed that C1 and C6 are substrates of cytochrome P-450. In contrast, alpha-tocopherol and its esters did not bind to cytochrome P-450 even at concentrations as high as 10 mmol/l. Apparently, C1 and C6 underwent biotransformation and were excreeted more quickly from the organism.

Antioxidant properties of rimantadine in influenza virus infected mice and in some model systems

Influenza virus infection is associated with development of oxidative stress in lung and blood plasma, viz. increase of primary and secondary lipid peroxidation products. It was established that rimantadine treatment led to a decrease of the products of lipid peroxidation in tissues of mice experimentally infected with influenza virus A/Aichi/2/68 (H3N2). The effect is strongest in blood plasma (a decrease of about 50%) and weaker in the lung (about 20%). To elucidate the mechanism of this action of rimantadine, experiments were carried out with some model systems. The capability of rimantadine to scavenge superoxide radicals (scavenging properties) was studied in a system of xanthine-xanthine oxidase to generate superoxide. The amount of superoxide was measured spectrophotometrically by the NBT-test and chemiluminesce. Rimantadine does not show scavenging properties and its antioxidant effect observed in vivo, is not a result of its direct action on the processes of lipid peroxidation and/or interaction with antioxidant enzymes. The antioxidant properties of rimantadine were investigated by measurement of induced lipid peroxidation in a Fe2+ and (Fe2+ - EDTA) system with an egg liposomal suspension. Our findings with model systems do not prove an antioxidant or prooxidant effect of the drug on the processes of lipid peroxidation. Apparently, the observed antioxidant effect of rimantadine in vivo is not connected directly with free radical processes in the organism.

Determination of malondialdehyde in biological samples by solid-phase extraction and high-performance liquid chromatography

An analytical procedure for determination of malondialdehyde in tissue homogenates and blood serum was developed. A reaction with 2,4-dinitrophenylhydrazine is used followed by cleaning up of the derivative by solid-phase extraction. The samples were analyzed by isocratic high-performance liquid chromatography (HPLC) using a narrow-bore HPLC-column. A good separation of the 1-pyrazole peak from that of 2,4-dinitrophenylhydrazine was observed. A high linear dependence was established by the concentration of 1-pyrazole in the range of 10-5000 ng/ml. The detection limit of the method applied for tissue homogenates and blood serum was approximately 10 ng/ml or lower, and RSD of the method was 9% (n = 8). The peak of 1-pyrazole for these samples was well separated from the other matrix peaks. Experiments carried out evaluated that the solid-phase extraction might be an effective step of the sample preparation, significantly increasing the selectivity of the analysis and the life-time of the column. The method seems to be applicable for determination of malondialdehyde in different biological samples.

Effect of vitamin E on lipid peroxidation and liver monooxigenase activity in experimental influenza virus infection

Influenza virus infection was associated with development of oxidative stress in liver of mice, viz. increase in amount of lipid peroxidation products, decrease in cytochrome P-450 and NADP. H-cytochrome c-reductase activity, and inhibition of liver monooxygenases (aniline hydroxylase, ethylmorphine-N-demethylase, amidopyrine-N-demethylase and analgin-N-demethylase). These effects were most pronounced on the 7th day after virus inoculation as compared to the 5th one. Supplementation of mice with vitamin E before virus inoculation leads to liver protection against oxidative stress and toxicosis. A marked decrease of lipid peroxidation products and an increase of cytochrome P-450 and activities of monooxygenases was established. The stabilizing effect of vitamin E was dose-dependent and was most pronounced on the 5th day after virus inoculation as compared to the 7th one.

Relationships between serum levels of autoantibodies against oxidized low density lipoproteins, lipid-soluble antioxidants and apolipoprotein B in patients with coronary heart disease

High affinity IgG autoantibodies against oxidized low density lipoproteins (oxLDLs), apolipoprotein B and lipid-soluble antioxidants--alpha-tocopherol and beta-carotene, were tested in patients with coronary heart disease. Correlation relationships between these parameters were analysed. Fifty one patients with coronary heart disease (37 males/14 females) defined as Q-wave myocardial infarction and/or stenosis of more than 50%, and 51 healthy blood donors (34 males/17 females) as controls participated in this study. LDLs were isolated by density gradient ultracentrifugation and oxidized with Cu2+. OxLDLs or native LDLs (nLDLs) were used as antigens in enzyme immunoassay (ELISA) to detect IgG autoantibodies in the serum. The contents of alpha-tocopherol and beta-carotene were measured by HPLC. Apolipoprotein B was determined by immunoturbidimetry. Correlation analysis of the parameters was carried out by Spearmann's test. Alpha-tocopherol was decreased significantly in the serum of patients with coronary heart disease (2.96+/-1.63 nmol/mg serum protein vs 6.23+/-2.28 nmol/mg serum protein in Control group) (p < 0.01). Also, the serum level of beta-carotene was decreased in patients with coronary heart disease (174.0+/-95.7 pmol/mg serum protein vs 313.2+/-141.5 pmol/mg serum protein in Control group) (p < 0.01), while apolipoprotein B was increased significantly (1.20+/-0.34 g/l in patients with coronary heart disease vs 0.86+/-0.23 g/l in Control group) (p < 0.001). In a previous study we established that the mean serum level of IgG autoantibodies against oxLDLs (expressed in optical density units) was about 2.5 times higher in patients with coronary heart disease as compared to control subjects (p < 0.001). A good positive linear correlation was observed between alpha-tocopherol and apolipoprotein B levels in Control group (r = 0.78, p < 0.001), as well as in the group of patients with coronary heart disease (r = 0.42, p < 0.001). Poor nonsignificant correlations were established between all another measured parameters. In conclusion, the lipid-soluble antioxidants--alpha-tocopherol and beta-carotene, are not informative with respect to the susceptibility of the serum to oxidative modifications and as to the extent of the subsequent humoral immune response. Presumably, the reduction of the correlation coefficient between apolipoprotein-B and alpha-tocopherol in patients with coronary heart disease in comparison with control subjects could provide indirect information on modifications of apolipoprotein-B and on a decrease of its susceptibility to interact with this major lipid-soluble antioxidant in atherogenesis.

Effect of some psychotropic drugs on the activated macrophage-induced luminol-dependent chemiluminescence

The effect of some psychotropic drugs on the activity of macrophages to produce superoxide radicals during phagocytosis was tested. Three-cyclic antidepressants, imipramine and amitriptyline, and the thioxanthene neuroleptic, chlorprothixene, were studied. The superoxide production was measured by luminol-dependent chemiluminescence. The drugs were investigated in the concentration range of 10(-7)-10(-4) mol/l. It was seen that all tested drugs caused a concentration-dependent decrease of the luminol-dependent chemiluminescence. The inhibitory effect of imipramine and amitriptyline on the macrophage superoxide production was moderate, while the effect of chlorprothixene was significantly stronger (a decrease more than 100 times that of macrophage chemiluminescence). Essentially, the luminol-dependent chemiluminescence reflects the level of superoxide radicals in the system. Therefore, the effect of drugs may be due to the possible activity for scavenging superoxide. In additional experiments with different systems of generations of O2- and different methods of registration, this possibility was discarded. Therefore, the effect of the drugs on the luminol-dependent chemiluminescence seems to be due to drug-induced decrease of the ability of activated macrophages to produce superoxide radicals.

Serum level of IgG autoantibodies against oxidized low density lipoproteins and lag-phase of serum oxidation in coronary heart disease--inverse correlation

High affinity IgG autoantibodies (ABs) against oxLDLs and lag-phase of serum oxidation were tested in patients with coronary heart disease (CHD). Fifty one (37 M/14 F) patients with CHD defined as Q-wave myocardial infarction and/or stenosis of more than 50% and 51 (34 M/17 F) healthy blood donors as controls participated in this study. LDLs were isolated by gradient ultracentrifugation and oxidized with CuSO4. The modified LDLs (oxLDLs) or native LDLs (nLDLs) were used as antigens in an enzyme immunoassay (ELISA) to detect IgG ABs in both groups. The serum was oxidized by CuSO4 and the oxidation was monitored spectrophotometrically at lambda = 234 nm to follow the formation of conjugated diens. The lag-phase (in minutes) is the interval between the addition of CuSO4 to the serum and the beginning of extensive oxidation (increasing absorbance at 234 nm). The concentrations of total cholesterol, triglycerides, HDL-cholesterol, apo-A and apo-B were measured as well. The mean level of ABs against oxLDLs (expressed as optical density units) was 0.590 +/- 0.330 in CHD-patients vs 0.244 +/- 0.200 in controls (p < 0.001). The lag-phase in minutes was 47.00 +/- 27.19 in CHD-patients and 80.23 +/- 26.30 in controls (p < 0.001). A negative correlation between ABs levels and lag-phase was established in CHD-patients (r = -0.69, p < 0.001) and controls (r = -0.62, p < 0.001). A poor correlation was established between ABs levels or lag-phase, on one hand, and other measured parameters. In conclusion, the lag-phase of serum oxidation by Cu2+ could be informative for LDL susceptibility to modification and the extent of consequent humoral immune response.

Pulmonary xanthine oxidase activity of rats exposed to prolonged immobilization stress

This study was designed to study xanthine oxidase (XO) and xanthine dehydrogenase (XD) activity in the lung of rats exposed to prolonged restraining immobilization stress. Immobilization caused more than twofold increase of xanthine oxidase activity in the rat lung. The activity of xanthine oxidase decreased in lung homogenates incubated at -20 degrees C for 24 h. The same incubation of homogenates from control rats caused a non-significant increase of the activity. No measurable NAD(+)-dependent xanthine dehydrogenase activity could be established in the lungs of both control rats and rats subjected to immobilization. All rats revealed methylene blue-dependent xanthine dehydrogenase activity which was more than two-times higher in the immobilized animals. Incubation at -20 degrees C for 24 h increased the methylene blue-dependent xanthine dehydrogenase activity in homogenates from control rats and decreased the enzyme activity in homogenates from immobilized rats. A working hypothesis was proposed for the sequence of events explaining the results obtained: XO-catalyzed generation of activated oxygen species may take place in the initiation of lipid peroxidation in the lung of rats immobilized for prolonged periods of time.

Effect of phenothiazines on activated macrophage-induced luminol-dependent chemiluminescence

The inhibitory effect of some phenothiazine neuroleptics (chlorpromazine, levomepromazine, thioridazine, promethazine and trifluoperazine) on the ability of rat peritoneal macrophages to produce O2- during phagocytosis was investigated. The superoxide radical release was estimated by measuring the luminol-dependent chemiluminescence (CL). The effect of drugs was studied in the concentration range of 0.1-100 mumol/l. Additional experiments to determine the ability of the drugs to scavenge O2- were carried out. They included measuring the effect of phenothiazines on the luminol-dependent CL in systems with enzymatically (xanthine-xanthine oxidase) and non-enzymatically (KO2) generated O2-. The ability of phenothiazines to scavenge O2- was additionally tested by a "non-luminescence" method in which the superoxide concentration was determined spectrophotometrically by the reduction of nitro blue tetrazolium to formazan. All drugs tested decreased significantly CL of stimulated macrophages at concentrations greater than 1 mumol/l. The C50 values were between 0.45 and 1.74 mumol/l. Also phenothiazines were found to act as scavengers of O2-. However, this effect occurred at significantly higher drug concentrations. The C50 values for 50% scavenging of O2- in systems with different sources of O2- were in the concentration range of 5-160 mumol/l. These results suggested that phenothiazines predominantly affected the ability of macrophages to produce O2- during phagocytosis. The findings may provide some insight into the untoward effects of the drugs tested.

Lipid peroxidation in the lung of rats exposed to endotoxin: effect of vitamin E supplementation

The aim of this work was to investigate the possibility for development of peroxidation in the lung of rats injected with endotoxin. The effect of vitamin E supplementation of the rats was also investigated. Vitamin E supplementation by itself did not cause visible differences or any pathological changes in the lung structure of rats as shown by routine histological examinations. The endotoxin-induced alterations of the lung structures were well expressed in vitamin E-non-supplemented rats, while they were rather negligible in vitamin E-supplemented rats. It was established also that endotoxin caused a 50% increase of the conjugated dienes in the lung of vitamin E-non-supplemented rats. For vitamin E-supplemented rats this increase was less than 13.5%. The fluorescent lipofuscine-like products of lipid peroxidation (known as one of the end products of lipid peroxidation) increased by 120% in vitamin E-non-supplemented rats after exposure to endotoxin, while in vitamin E-supplemented rats this increase did not exceed 26%. Exposure to endotoxin of both vitamin E-non-supplemented and vitamin E-supplemented rats did not lead to significant changes of the lung fatty acid composition. On the basis of these results we assumed that the endotoxin-induced changes of lung structures involve, at least in part, free radical-mediated damage of the lung membrane lipids and proteins.

Nitrous oxide with fentanyl and droperidol minimizes lipid peroxidation in the liver

We have studied the level of lipid peroxidation in the liver of rats exposed to nitrous oxide plus oxygen or injected with droperidol of fentanyl. The effect of nitrous oxide used in combination with droperidol and fentanyl was also investigated. All the tested anaesthetics caused lipid peroxidation in the rat liver. It seems likely, however, that the mechanism by which droperidol and fentanyl initiate lipid peroxidation differs from that which nitrous oxide uses. Free radical products and/or activated oxygen species are produced during fentanyl and droperidol metabolism in the liver. However, nitrous oxide is not metabolized in the liver and probably undergoes one electron reduction outside the liver thus producing free radical products and/or activated oxygen species which are able to diffuse and initiate lipid peroxidation in the liver. It was also found that the level of lipid peroxidation in the liver of rats injected with droperidol and fentanyl and then exposed to nitrous oxide was low and close to that of the control animals. We suggest that, when used in combination, the products generated outside the liver as a result of nitrous oxide metabolism are transported to the liver and take part in reactions with the products of the metabolism of droperidol and fentanyl, thus decreasing the concentration of the species able to initiate lipid peroxidation.

Polyamines as modulators of lipoperoxidation

The polyamines spermine and spermidine and the diamine putrescine inhibit lipid peroxidation in phospholipid liposome suspensions and rat liver homogenates. Using the chemiluminescence technique the antioxidant activity of polyamines was found to be due to reactions with the free radical intermediates of lipid peroxidation and/or superoxide radicals. Also, the antioxidant action of polyamines correlated with the amount of their amino groups: the antioxidant activity increases from putrescine to spermine.

[The efficiency of the action of alpha-tocopherol and its homologs on luminol-dependent chemiluminescence induced by (Fe2+ + NADP.H) and (Fe2+ + ascorbate) systems in rat liver microsomes]

The effects of alpha-tocopherol (C16) and its homologues with different chain length (6-hydroxychromanes-C1, C6, C11) on lipid peroxidation induced luminol-dependent chemiluminescence in rat liver microsomal suspensions were studied. It was shown that C1, C6 and C11 inhibited the (Fe(2+) + ascorbate)-and (Fe(2+) + NADP.H)-induced chemiluminescence. The inhibitory effect was decreased in the order: C1 C6 C11, C16 was not influenced chemiluminescence. The possible reason underlying these differences was discussed: different efficiency of interaction of C16 and its homologues with hydroxyl and superoxide radicals, which initiate the luminol-dependent chemiluminescence. It was concluded that C16 (in concentration below 0.5 mM) was not interacted with hydroxyl and superoxide free radicals, generated in microsomal suspensions under (Fe(2+) + ascorbate)- and (Fe(2+) + NADP.H)-dependent lipid peroxidation.

[The effect of isoprenaline on the aggregation and adhesive properties of circulating rat neutrophils]

It is well known that isoprenaline (1-3-4-dihydroxy-phenyl-isopropyl-aminoethanol) (IP) induce necrosis in myocardium of laboratory animals, which is similar to pathomorphological development of clinical myocardial infarction. This process is accompanied by peripheral blood leukocytes. The IP-inductor effects on arachidonate-dependent aggregation and endothelial adhesion of peripheral blood neutrophils (PN) were studied in this paper. The enhancement of PN aggregational properties within 2-4 hours after intravenous IP-injection to rats was demonstrated. Using the method of vital microscopy it was shown that intravenous IP-injection to rats or IP-application on rat mesentery lead to an increase of leukocyte's marginal pool on the endothelium of mesenteric venules. However, it was noted that the change of cell functional properties is not due to the direct influence of IP on PN. The pathogenetic mechanisms of IP-induced cardiomyopathy in rats were discussed.

Mercaptodextran--a new copper chelator and scavenger of oxygen radicals

The therapy of copper poisoning with mercaptodextran inhibits the copper-induced haemolysis, whereas 2,3- dimercaptopropanesulfonic acid (DMPS) may accelerate such haemolysis. Some aspects of the mechanisms of these effects were investigated. The possible generation of activated oxygen species during the interaction of Cu++ and chelating thiols was studied using a chemoluminiscent method detecting oxygen radicals. It was found that incubation of DMPS with copper ions or erythrocyte membranes was accompanied by generation of oxygen radicals. Mercaptodextran added to similar suspensions did not lead to oxygen radical production. And unlike DMPS, mercaptodextran acted as a scavenger of radicals generated by the xanthine oxidase/acetaldehyde system. The different ability of the chelating thiols to cope with free radicals may explain their different potentials to protect against copper-induced haemolysis. Our results also indicate that mercaptodextran may be a useful therapeutic agent in cases of haemolytic crisis in Wilson's disease.

The interaction of copper (Cu++) with the erythrocyte membrane and 2,3-dimercaptopropanesulphonate in vitro: a source of activated oxygen species

The therapy of copper poisoning and of Wilson's disease with 2,3-dimercaptopropane-1-sulphonate (DMPS) may increase the copper-induced haemolysis. Some aspects of the mechanism of this effect were investigated. The possible generation of activated oxygen species during the interaction of Cu++ and DMPS was studied using a chemiluminescent method detecting oxygen radicals. It was found that incubation of DMPS with copper ions (free or bond with erythrocyte membranes) is accompanied with generation of oxygen radicals. Activated oxygen species produced via O2- are able to increase the haemolytic effects of cupric salts. Hence DMPS treatment in cases of copper poisonings or Wilson's disease may involve risk of side effects on the basis of activated oxygen species generation.

Generation of active forms of oxygen at Cu2+-catalyzed oxidation of haemoglobin--haemiluminescent study

Haemiluminescent method is used to study the generation of active forms of oxygen upon Cu2+-catalyzed oxidation of guinea-pig oxyhaemoglobin. It has been found that Cu2+ markedly catalyses the oxidation of haemoglobin to methaemoglobin. The established inhibition of the oxidative process by the enzymes superoxide dismutase and catalase indicates the participation of O-2 and H2O2 in it. The haemiluminescent studies prove that O-2 and H2O2 are produced during the oxidation of haemoglobin. The production of active forms of oxygen is at least partly due to release of oxygen bound in the oxyhaemoglobin molecule in the form of superoxide radical. In addition to this, bivalent copper ions, oxidizing the haemoglobin SH-groups, are reduced to monovalent, which in their turn may reduce the molecular oxygen to O-2. The scheme of the primary acts of interaction in the Cu2+--HbO2--O2 system is proposed, leading to O-2 production, and through it--to other active oxygen forms.

[Hemolytic action of lead in in vitro experiments]

The effect of some oxidizers and antioxidants on hemolytic action of lead has been studied in in vitro experiments performed with guinea-pig red cells. It has been shown that oxygen and hydrogen peroxide enhance the hemolysis while antioxidants prevent the hemolytic action of lead ions. This suggests the oxidative mechanism of the lead-induced hemolysis.