Lipid peroxidation in rat lung induced by neuroleptanalgesia and its components.

The aim of the present work was to determine the likelihood of lipid peroxidation in the lungs of rats subjected to neuroleptanalgesia and its components. In particular, the effect of fentanyl, droperidol, a nitrous oxide/oxygen mixture when used separately or in combination, on the lung level of lipid peroxidation was investigated. The in vitro antioxidant properties of fentanyl and droperidol were also tested. Lipid peroxidation was evidenced by the endogenously generated conjugated dienes and fluorescent products of lipid peroxidation and the decrease in lung vitamin E content. It was found that fentanyl and droperidol, used separately or in combination, did not induce lipid peroxidation in the rat lung, while the exposure of rats for 120 min to a nitrous oxide/oxygen mixture (2:1 v/v) led to well-expressed peroxidation. The (N2O + O2)-pro-oxidant action was significantly inhibited in rats previously injected with fentanyl and/or droperidol. The results show that the application of fentanyl, droperidol and (N2O + O2), as in neuroleptanalgesia, ensures minimal lipid peroxidation in the lung. In addition, we found that fentanyl and droperidol were able to inhibit the Fe(2+)-catalysed lipid peroxidation in lung homogenate. We speculate that the inhibitory effect of fentanyl and/or droperidol on the (N2O + O2)-induced lipid peroxidation in the rat lung may be caused directly by their antioxidant properties. However, another explanation seems to be possible. The free radicals that are produced during the metabolism of fentanyl and droperidol may react with the radicals generated during the one-electron reduction of nitrous oxide. Such reactions will obviously reduce the free radical concentration in the organism and, hence, the likelihood of initiating lipid peroxidation.

Oxidation of low density lipoproteins leads to disturbance of their binding with alpha-tocopherol.

The dynamics of binding of exogenous alpha-tocopherol (alpha-T) added to native or oxidatively modified LDLs (LDLs or oxLDLs) were investigated. Venous blood from 31 clinically healthy blood donors (15 males and 16 females) was used. LDLs were isolated by density gradient ultracentrifugation. LDLs were oxidized in vitro by CuSO4. LDLs or oxLDLs were enriched with exogenous alpha-T (initial concentrations: 0; 10; 20; 50; or 100 nmol per mg protein). The contents of alpha-T in LDLs or in oxLDLs were measured by HPLC. Lag-phase of LDL oxidation before or after saturation with alpha-T was recorded. Correlation analysis of the lag-phase of LDL oxidation and alpha-T content in LDLs was carried out by the method of Esterbauer et al. The experimental results demonstrated that: (i) alpha-T was incorporated into native LDLs to a higher extent as compared to oxLDLs. (ii) A saturation of LDLs and oxLDLs with alpha-T was observed. (iii) A positive correlation was observed between the duration of the lag-phase of LDL oxidation in vitro and the content of alpha-T in LDLs. (iv) Based on LDL saturation with alpha-T, the persons could be classified in two groups: LDLs from group I of 26 persons were found to incorporate exogenous alpha-T to the extent of 1.8 to 3 times its initial concentration; LDLs from group II of 5 persons incorporated little or no exogenous alpha-T. In the first group, oxidation of LDLs lead to a considerable decrease in alpha-T dependent variable k and to a moderate reduction of alpha-T-independent variable alpha in the equation of Esterbauer et al.: lag-phase = k.[alpha-tocopherol]+alpha. In the second group, oxidation of LDLs lead to insignificant changes in k, as well as in a. (v) According to the levels of k and a the native LDLs from the second group of 5 persons were very close to oxLDLs from the first group of 26 persons. Presumably, native LDLs from the second group of persons were initially oxidatively modified, and probably this will be a risk group in relation to atherogenic disorders.

Lipid peroxidation in lung of rat stressed by immobilization: effects of vitamin E supplementation.

This study was carried out to examine the possibility of initiation of lipid peroxidation in the lung of Wistar albino male rats stressed by immobilization. The effects of vitamin E supplementation were also investigated. We found that immobilization of rats with normal pulmonary content of vitamin E caused lipid peroxidation in the lung. Decrease of the lung content of unsaturated fatty acids and vitamin E was also established. The immobilization-induced changes of all of these parameters were significantly inhibited by vitamin E injection (100 mg/kg body weight) for 7 days. A possible sequence of events leading to the initiation of lipid peroxidation and lung cell membrane damage in rats stressed by immobilization is discussed.

Oxidative damage of the membrane lipids after electroporation.

Electric field pulses used for cell manipulation can cause irreversible cell damage. The mechanisms of the processes leading to such cell damage are very complicated. Our work demonstrated that exponential electric pulses with intensity of 2-7.5 kV/cm and duration of 5.2 ms were able to initiate peroxidation of fatty acid emulsions, liposomal membranes, red blood and Ehrlich ascite tumor cells. Electric pulses-induced peroxidation of erythrocyte membranes was followed by hemolysis. The electric treatment caused damage of E. coli membrane lipids which was accompanied by decreased cell survival. All these effects depended on field intensity. A relatively good correlation between pulse-induced peroxidation of erythrocyte membranes and hemolysis was observed. These results suggest that free radical mediated processes as lipid peroxidation and/or lipid degradation or fragmentation may be possible causes for electric pulses-induced irreversible cell damage.

Study of activated oxygen production by some thiols using chemiluminescence.

2-3-dimercapto-1-propane sulfonic acid, D-penicillamine and meso-dimercapto succinic acid, drugs widely applied as antidota against metal poisoning, and cysteine and glutathione were studied with respect to their ability to generate and to scavenge superoxide anion radical. Superoxide production and scavenging were tested by means of luminol-dependent chemiluminescence. In presence of 1 mumol/l ADP-Fe3+ only cysteine and meso-dimercapto succinic acid induced chemiluminescence which could be inhibited by superoxide dismutase. 2,3-dimercapto-1-propane sulfonic acid, D-penicillamine and glutathione acted as O2- scavengers. These thiols inhibited O2(-)-dependent lipid peroxidation thus acting as antioxidants, whereas cysteine and meso-dimercapto succinic acid accelerated peroxidation. It is suggested that the toxic side effects of thiols may be due to their ability to generate or to scavenge free radicals.

[Lipid peroxidation in emotional stress in rats: correlation with parameters of open field behavior]. / Perekisnoe okislenie lipidov pri émotsional'nom stresse u krys: korreliatsiia s parametrami svododnogo povedeniia.

TBA-reactive products were measured in the brain, liver, and heart of Wistar rats in control conditions and after 24 h immobilization. Animals were subjected to the open field test before and after the immobilization. Behavior patterns, gastric mucosa alterations and MDA accumulation in organs suggested that immobilization as well as food and water deprivation were all strong stressor stimuli. Initial open field behavior characteristics were significantly correlated with MDA contents in various tissues under emotional stress.

Priming of phagocytes by cytokines and water-soluble products of lipid peroxidation.

It is well known that during certain pathological processes phagocytes acquire the ability to generate activated oxygen species during phagocytosis. The priming of phagocytes by cytokines and water-soluble products of lipid peroxidation (LPO) is described. Preincubation of human polymorphonuclear leukocytes (PMNL) with the water-soluble products of LPO or oxidised liposomes for 15-20 min at 37 degrees C enhanced their functional activity when they were stimulated by opsonised zymosan or latex particles. There was a 2-3-fold increase in luminol-dependent chemiluminescence response of cells stimulated in this way, and an increase in Fc-receptor expression on the PMNL surface. An endogenous cytokine alone did not activate the phagocytes for an oxidative burst response, but preincubation of murine peritoneal macrophages (MP) and human PMNL with cytokines (molecular mass 20-30 kDa) for 3-48 h at 37 degrees C enhanced the cell chemiluminescence response to opsonised zymosan by a factor of 5-9 for MP and a factor of 2-3 for PMNL. Treatment of phagocytes with the cytokine complex also increased other effector functions of the phagocytes such as tumouricidal activity, phagocytosis, secretion of interleukin-1, and antiparasitic activity. The protein synthesis inhibitor cycloheximide abolished cytokine-induced priming of MP (but not of PMNL). The mechanisms of short-term and prolonged priming of the two types of phagocytes (MP and PMNL) are discussed.

[Functional activity of polymorphonuclear leukocytes in isoprenaline-induced cardiomyopathy in rats]. / Funktsional'naia aktivnost' polimorfnoiadernykh leikotsitov krovi pri izoprenalinovoi kardiomiopatii krys.

The article studies the dynamics of changes of the parameters of the functional activity using chemiluminescent and turbidimetric methods as well as blood plasma myocardium and liver homogenates in isoprenaline cardiomyopathy in rats. Mechanisms of pathogenesis of isoprenaline-induced cardiomyopathy in rats is being discussed.

Effect of oxidized phospholipids on the chemiluminescence of zymosan-activated leukocytes.

The effect of liposomes with different degree of oxidation on the zymosan-induced chemiluminescence (CL) of leukocytes was investigated. Non-oxidized liposomes did not influence significantly the CL response of leukocytes. In contrast previously oxidized liposomes increased CL even if liposomes and cells were separated by a dialysis membrane. Based on the observed increase of luminol-activated CL by oxidized liposomes, lipid peroxidation (LPO) products may be suggested to enhance cell activation. Zymosan-activated leukocytes did not affect the amount of malondialdehyde (MDA) in non-oxidized liposomes unless iron salts were added. Fe3+ + ADP added to non-oxidized liposomes triggered LPO. Both catalase and superoxide dismutase (SOD) prevented the effect. In experiments with previously oxidized liposomes the activated oxygen species produced by leukocytes did not increase the amount of MDA; on the contrary, they decreased it both in the presence and in the absence of chelated iron in the liposome suspension. The reaction between lipid hydroperoxide and O2- widely accompanied by CL. SOD decreased CL in this system by a factor of 1.7. On the other hand, peroxidized lipids may "opsonize" initially inactive particles: oxidized liposomes increased CL response of leukocytes similarly as opsonized zymosan routinely used as a phagocyte activator.

[Initiation of peroxidation of liposome membrane lipids by activated polymorphonuclear leukocytes]. / Initsirovanie perekisnogo okisleniia lipidov membran liposom aktivirovannymi polimorfnoiadernymi leikotsitami krovi.

The influence of active oxygen forms produced by zymosan-stimulated polymorphonuclear leukocytes (PMNL) on the initiation of liposome lipid peroxidation has been studied. It has been shown, by measuring the concentration of TBA-active products, that lipid peroxidation induced by PMNL stimulation occurs only in the presence of Fe-ADP. This fact demonstrates that OH'-radicals are responsible for the initiation of lipid peroxidation. Superoxide dismutase and catalase almost completely inhibited PMNL-stimulated peroxidation. The results obtained suggest that active oxygen forms that appear during PMNL stimulation can migrate at a considerable distance from the place of their origin, initiating peroxidation of cell membrane lipids and lipoproteins in the presence of Fe ions, which seems to underlie bacteriocidal and cytotoxic action of phagocytes.

[Study of monoamine oxidase from human placenta mitochondria by the chemoluminescence method]. / Issledovanie monoaminoksidazy mitokhondrii platsenty cheloveka metodom khemiliuminestsentsii.

The activity of monoamine oxidase from human placenta mitochondria was determined with 2-phenylethylamine and benzylamine as substrates by the generation of hydrogen peroxide in a conjugated luminol-peroxidase system, using the chemiluminescence method. The monoamine oxidase was found to oxidize at a high rate MAO substrates and revealed high sensitivity to clorgyline, a specific inhibitor of monoamine oxidase type A. It was shown that the use of the chemiluminescence technique for determining the monoamine oxidase activity gives the results that are fully consistent with those obtained by other methods.

[Induction of lipid peroxidation in the erythrocytes during cholesterol oxidation catalysed by cholesterol oxidase]. / Induktsiia perekisnogo okisleniia lipidov v éritrotsitakh v khode okisleniia kholesterina, kataliziruemogo kholesterinoksidazoi.

Using the chemiluminescence technique to assay the activity of cholesterol oxidase it has been shown that enzymic oxidation of cholesterol to cholest-4-en-3-one red cell membranes is accompanied by accumulation of lipid peroxidation products--malonyl dialdehyde (MDA). The amount of MDA formed was dependent on the amount of cholesterol oxidized. The free radical scavenger 4-methyl-2,6-ditretbutylphenol, the transition metal chelator EDTA and catalase inhibited lipid peroxidation in red blood cells. The participation of OH radicals in the initiation of lipid peroxidation in red cell membranes in the course of cholesterol oxidation is discussed.

The interaction of copper chloride with erythrocyte membrane as a source of activated oxygen species. A chemiluminescent study.

The possibility for the generation of activated oxygen species during the interaction between copper chloride and erythrocyte membranes was investigated. A chemiluminescent method for detecting superoxide radicals and hydrogen peroxide was used. It was found that the interaction of CuCl2 with erythrocyte membrane is accompanied with O-2 and H2O2 generation. On the base of this result it is proposed that the activated oxygen species generated by CuCl2-membrane interaction may be able to initiate peroxidative breakdown processes in erythrocytes eventually leading to haemolysis.

HgCl2 increases the methemoglobin prooxidant activity. Possible mechanism of Hg2+-induced lipid peroxidation in erythrocytes.

In an attempt to elucidate the mechanism of initiation of peroxidation in HgCl2-treated erythrocytes, the effect of HgCl2 on methemoglobin-catalyzed lipid peroxidation was studied. It was found that HgCl2 reinforces the prooxidant action of methemoglobin. This effect seems not to be due to dissociation or degradation of the hemoglobin molecule to heme-containing fragments or iron-containing products of low molecular weight. The results obtained indicate that Hg2+ increases the binding of oxy- and methemoglobin to liposomes. A suggestion is made that the acceleration of methemoglobin-catalyzed peroxidation by HgCl2 is mainly due to increased binding of methemoglobin to liposomes. On the basis of these results and the results obtained previously the possible mechanism of initiation of peroxidation in Hg2+-treated erythrocytes is discussed.

Binding of haemoglobin to the red-cell membrane in the presence of copper chloride.

Methaemoglobin may be an important factor for initiation and development of lipid peroxidation in Cu(II)-treated red blood cells. It seems likely that the initiation of peroxidation by methaemoglobin is only possible if direct contact between haemoglobin molecule and the cell membrane is realized. In view of this, the binding of haemoglobin to the red-blood-cell membrane in the presence of CuCl2 was studied. It was found that the haemoglobin quenching of the fluorescence of 12-(9-anthroyl)stearic acid-labelled red-blood-cell membranes greatly increases in the presence of CuCl2. This effect is relatively independent of pH and the ionic strength of the medium, indicating that in this case the binding of haemoglobin is not electrostatic in nature. The haemoglobin quenching of the fluorescence of the inside-out and the right-side-out resealed ghosts were almost the same in the presence of CuCl2. This result suggests that, in the presence of ionic copper, both surfaces of the membrane possess approximately equal amounts of sites for the binding of haemoglobin.

A chemiluminescent method for measurement of activated oxygen forms in biological fluids and homogenates.

A chemiluminescent method for measuring the concentration of activated oxygen species (O-2 and H2O2) is described. Its main features are: high sensitivity (10(-9) M H2O2), its applicability to systems with high optical absorbance in the visible spectral region, a wide linear dynamic range, and the possibility for recording the kinetics of the processes, in which activated oxygen species are involved.

Hemoglobin-catalyzed lipid peroxidation in the presence of mercuric chloride.

In order to elucidate the possible mechanism of initiation of peroxidative processes in Hg2+-treated erythrocytes, the effect of HgCl2 on hemoglobin-catalyzed peroxidation of phospholipid liposomes was studied. It was demonstrated that HgCl2 significantly increases the rate of hemoglobin-catalyzed peroxidation. The addition of superoxide dismutase and catalase partially inhibits this effect. Furthermore, it was found that HgCl2 potentiates the hemoglobin oxidation. A suggestion was made that the acceleration of hemoglobin-catalyzed peroxidation by HgCl2 is associated at least in part with the increased production of superoxide anion radicals from hemoglobin.

Possible contribution of oxyhemoglobin to the iron-induced hemolysis simultaneous effect of iron and hemoglobin on lipid peroxidation.

The mechanism of iron toxicity in iron overloaded patients is not well established. A hypothesis was put forward that free radical processes are involved. Our earlier study indicates that iron-induced hemolysis is preceded by peroxidation of the membrane lipids. In the present work the simultaneous effect of iron and hemoglobin on lipid peroxidation was studied. It was found that in hemoglobin-containing liposome suspensions Fe2+ in concentrations above 10(-5) M inhibits the peroxidation, while Fe3+ drastically potentiates it, with concomitant transformation of oxyhemoglobin to methemoglobin. The experiments with scavengers of activated oxygen indicate superoxide anion radical (O-.2), hydroxyl radical (OH.) and singlet oxygen (1O2) participation. The possible mechanism of the phenomenon is discussed. A conclusion is drawn that the toxic effect of Fe3+ may be associated not only with iron--membrane interaction, but also with increased methemoglobin formation and O-.2 release.