The parameters of antioxidant status of tissues in the offspring of tundra vole (Microtus oeconomus Pall.) inhabiting areas with increased natural radioactivity

The parameters of the lipid peroxidation regulatory system (the antioxidative and antiperoxidant activities, the peroxide content, the lipid peroxidation intensity) in the tissues and the activities of the antioxidative defence enzymes (the peroxidase activity in blood, the superoxide dismutase activity in the blood erythrocytes) are studied in progeny of tundra vole which are reproduced from parent inhabiting areas with different radioecological environment during a long time. The progeny had the preservation of the changed antioxidant status. The scale of the changing of the investigating parameters depend on the state of radionucleoids contamination of areas where tundra voles are caught, sex of rodents, the content of antioxidants in lipids of tissues of parents.     

Effect of diltiazem on cholesterol and phospholipid content and intensity of free radical oxidation process in plasma membranes of cardiomyocytes and blood cells in experimental hypercholesterolemia

Changes of lipid structure and function in membranes of cardiomyocytes and blood cells of rabbits were investigated under the effect of experimental hypercholesterolemia and calcium antagonist diltiazem influence. The activity of peroxide oxidizing of lipids (POL) and protein in membrane of sarcolemma, blood cells and serum, and activity of the same enzymes of antioxidant system--catalase (CAT) and superoxide dismutase (SOD) were studied as well. The research marks that diltiazem was manifested by activation of antioxidant system in cardiomyocytes and membrane sarcolemma, normalization of its lipid structure and by the decrease of the content of products POL and oxidizing of protein.     

WGA reduces the level of oxidative stress in wheat seedlings under salinity

Protective effect of exogenous wheat germ agglutinin (WGA) on wheat seedling (Triticum aestivum L.) during salinity stress was studied. In particular, we examined the state of pro- and antioxidant systems as well as the level of peroxide oxidation of lipids and electrolyte leakage under control conditions and when stressed with NaCl. Generation of superoxide anions and activity of both superoxide dismutase (SOD) and peroxidase increased during saline stress. Accumulation of O₂ ^·− resulted in peroxide oxidation of lipids and electrolyte leakage in response to stress. The injurious effect of salinity on root growth of seedlings was manifested by a decreased mitotic index (MI) in apical root meristem. This study show that WGA pretreatment decreased salt-induced superoxide anion generation, SOD and peroxidase activities, levels of lipid peroxidation and electrolytes leakage as well as correlating with a reduction in the inhibition of root apical meristem mitotic activity in salt-treated plants. This suggests that exogenous WGA reduced the detrimental effects of salinity-induced oxidative stress in wheat seedlings. Thus WGA effects on a balance of reactive oxygen species (ROS) and activities of antioxidant enzymes may provide an important contribution to a range of the defense reactions induced by this lectin in wheat plants.     

Effect of reactive oxygen species on the metabolism of tryptophan in rat brain: Influence of age

In an earlier study, oxidation of tryptophan hydroxylase was implicated as its affinity was decreased with aging in rat brain. To establish any potential link between its oxidative damage and aging, we have determined the activities of antioxidant enzymes in midbrain, pons and medulla of 2, 12 and 24 month old Fisher 344 BNF1 rats. The results obtained suggest that the activities of antioxidant enzymes varied considerably with age and brain regions studied. Activities of Cu/Zn superoxide dismutase and glutathione peroxidase were found to increase from 2 to 12 months and then decrease in 24 month old rats. However catalase activity decreased consistently with the age. A parallel increase in the carbonyl content was observed in these brain regions indicating the oxidation of proteins. Reactive oxygen species when included in the incubation mixture decreased the activity of tryptophan hydroxylase in a concentration dependent manner. The loss of tryptophan hydroxylase activity induced by hydrogen peroxide and superoxide anion was prevented by catalase. However superoxide dismutase did not provide such protection. Sulfhydryl agents, cysteine, glutathione and dithiothreitol partially prevented the loss of activity. These studies suggest an involvement of reactive oxygen species for sulfhydryl oxidation of tryptophan hydroxylase in aging.     

Role of free radicals in Plasmodium berghei infected Mastomys natalensis brain.

Lipid peroxide, lipid hydroperoxide, reduced glutathione, oxidised glutathione, lipofuscin contents and the activity of the enzyme superoxide dismutase were assessed in P. berghei infected M. natalensis brain. The results showed significant increase in the levels of lipid peroxides, lipid hydroperoxides and lipofuscin in brain subcellular fractions of P. berghei infected M. natalensis. Furthermore, a depressed superoxide dismutase activity was observed along with regulation in glutathione content. An elevated level of lipid peroxidation products along with depressed activity of scavengers in brain during malaria highlights the role of free radicals in malarial pathology.     

Adriamycin stimulated superoxide formation in submitochondrial particles.

Adriamycin (doxorubicin), an anticancer agent, stimulated the formation of superoxide in submitochondrial particles isolated from bovine heart. Superoxide formation was detected by oxygen uptake, by the cooxidation of epinephrine to adrenochrome and by the reduction of acetylated cytochrome c. These processes were sensitive to superoxide dismutase (SOD). Rotenone-insensitive oxidation of NADH by the mitochondrial respiratory chain in the presence of oxygen caused the formation of approx 4 nmol of superoxide per min/mg of protein. Adriamycin at a concentration of 400 micron stimulated the rate of superoxide formation 6-fold to 25 nmol.min-1.mg-1, but this was not a maximum rate. Approximately 50 micron adriamycin was estimated to be sufficient for obtaining one-half maximal stimulation. Hydrogen peroxide accumulated as a final reaction product. Measurements of the relative catalase activity of blood-free tissues of rabbits and rats indicated that heart contained 2 to 4% of the catalase activity of liver or kidney. An enhanced production of superoxide and hydrogen peroxide and the relatively low catalase content of heart tissue may be factors in the cardiotoxicity induced by adriamycin chemotherapy if a similar reaction occurs in vivo.     

Superoxide-dependent redox cycling of citrate-Fe3+: evidence for a superoxide dismutaselike activity

Citrate-Fe3+, reportedly a physiological chelate, exhibits superoxide dismutaselike activity, as evidenced by the inhibition of xanthine oxidase-dependent cytochrome c reduction; the dismutation of xanthine oxidase-generated superoxide to hydrogen peroxide and oxygen, and the enhanced disproportionation of potassium superoxide. The catalytic activity of citrate-Fe3+ corresponds, on a molar basis, to 0.03% of that of copper- and zinc-containing superoxide dismutase. Although weak, this activity enables citrate-Fe3+ to inhibit superoxide and ADP-Fe3+ -dependent peroxidation of extracted microsomal lipids. Also, the dismutase activity of citrate-Fe3+ interferes with its ability to promote lipid peroxidation. It is proposed that chelation of Fe3+ by citrate may represent a protective mechanism against the deleterious consequences of superoxide generation.     

Generation of hydrogen peroxide during the oxidation of L-phenylalanine by Proteus mirabilis isolated membranes

In the process of L-phenylalanine oxidation by Proteus mirabilis cytoplasmic membrane, hydrogen peroxide was produced at a rate corresponding to 1-3 per cent of the total electron flow (30-110 nmoles min-1mg-1). Peroxide was estimated using a fluorimetric assay with horseradish peroxidase, or by anodic oxidation on a platinum electrode. When using the former method, superoxide dismutase decreased the apparent yield of peroxide, a fact suggesting that H2O2 was in part the dismutation product of superoxide radicals. However the superoxide dismutase effect could be an artefact due to the generation of some superoxide during the peroxidatic reaction in the assay. Adrenaline was the reagent used for the detection of superoxide. There was no significant emergence of superoxide as the result of phenylalanine oxidation by the membrane (specific activity lower than 1-2 nmoles min-1mg-1). Thus it seemed that superoxide was not an intermediate for the bulk of H2O2 formed in this system. According to the results, peroxide was probably formed at a stage of electron transport earlier than the cytochrome level. The membrane phenylalanine dehydrogenase could be a site where peroxide was evolved in these experiments.     

Effects of piperine on antioxidant pathways in tissues from normal and streptozotocin-induced diabetic rats

Using diabetes mellitus as a model of oxidative damage, this study investigated whether subacute treatment (10 mg/kg/day, intraperitoneally for 14 days) with the compound piperine would protect against diabetes-induced oxidative stress in 30-day streptozotocin-induced diabetic Sprague-Dawley rats. Liver, kidney, brain, and heart were assayed for degree of lipid peroxidation, reduced and oxidized glutathione (GSH and GSSG, respectively) content, and activities of the free-radical detoxifying enzymes catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase. Piperine treatment of normal rats enhanced hepatic GSSG concentration by 100% and decreased renal GSH concentration by 35% and renal glutathione reductase activity by 25% when compared to normal controls. All tissues from diabetic animals exhibited disturbances in antioxidant defense when compared with normal controls. Treatment with piperine reversed the diabetic effects on GSSG concentration in brain, on renal glutathione peroxidase and superoxide dismutase activities, and on cardiac glutathione reductase activity and lipid peroxidation. Piperine treatment did not reverse the effects of diabetes on hepatic GSH concentrations, lipid peroxidation, or glutathione peroxidase or catalase activities; on renal superoxide dismutase activity; or on cardiac glutathione peroxidase or catalase activities. These data indicate that subacute treatment with piperine for 14 days is only partially effective as an antioxidant therapy in diabetes.     

Changes in oxidative stress parameters and acid phosphatase activity in the pre-regressing and regressing tail of Indian jumping frog Polypedates maculatus (Anura,Rhacophoridae)

Activities of acid phosphatase (normal and Co²⁺-sensitive), superoxide dismutase and catalase and levels of lipid peroxidation, hydrogen peroxide were compared in the tails of tadpoles of stage III, XVIII, XXI and XXIII, respectively, of the Indian Jumping frog Polypedates maculatus. It is noticed that acid phosphatase activity (normal and Co²⁺-sensitive), and levels of lipid peroxidation and hydrogen peroxide increased during tail regression. There is also an increase in the level of superoxide dismutase and catalase in the regressing tail. A positive correlation between activity of acid phosphatase and lipid peroxidation, hydrogen peroxide and lipid peroxidation, acid phosphatase and hydrogen peroxide was noticed in the tail of tadpoles during different developmental stages, suggesting a critical interaction between reactive oxygen species and lysosomal activity during metamorphosis.     

Use of a heptane-isopropanol system for extraction of primary lipid peroxidation products

Products of different lipids oxidation were studied for the peculiarities of their distribution in the extracting system heptane--isopropanol widely used in spectrophotometric determination of primary products of peroxide oxidation of lipids. It is shown that hydroperoxides of phospholipids and their reduction products almost completely transfer to the alcohol phase while hydroperoxides of triacetin and cholesterol esters are 70-85% extracted by heptane. Thus, it is necessary to analyze the alcohol phase when using the systems heptane-isopropanol to determine the content of primary products of lipid peroxide oxidation in those tissues, where phospholipids are the basic oxidation substrates.     

Comparison of redox state of cells of tatar buckwheat morphogenic calluses and non-morphogenic calluses obtained from them

Intracellular content of hydrogen peroxide and of the product of lipid peroxidation malonic dialdehyde as well as activity of antioxidant enzymes catalase, ascorbate peroxidase, and superoxide dismutase were studied in cells of morphogenic and derived from them non-morphogenic calluses of tatar buckwheat Fagopyrum tataricum L. Non-morphogenic calluses were characterized by significantly higher content of hydrogen peroxide and malonic dialdehyde, low catalase activity, and high activity of superoxide dismutase compared to morphogenic cultures. The results may indicate that cells of non-morphogenic calluses are in the state of continuous oxidative stress. Nevertheless, proliferative activity of non-morphogenic cultures and the biomass increase significantly exceeded these parameters in morphogenic calluses. An analogy is drawn between animal cancer cells and non-morphogenic plant calluses.     

The involvement of superoxide and iron ions in the NADPH-dependent lipid peroxidation in human placental mitochondria

Incubation of human term placental mitochondria with Fe2+ and a NADPH-generating system initiated high levels of lipid peroxidation, as measured by the production of malondialdehyde. Malondialdehyde formation was accompanied by a corresponding decrease of the unsaturated fatty acid content. This NADPH-dependent lipid peroxidation was strongly inhibited by superoxide dismutase and singlet oxygen scavengers, markedly stimulated by paraquat, but was not affected by hydroxyl radical scavengers. Catalase enhanced the production of malondialdehyde by placental mitochondria. The effects of catalase and hydroxyl radical scavengers suggest that the initiation of NADPH-dependent lipid peroxidation is not dependent upon the hydroxyl radical produced via an iron-catalyzed Fenton reaction. These studies provide evidence that hydrogen peroxide strongly inhibits NADPH-dependent mitochondrial lipid peroxidation. The inhibitory effect of superoxide dismutase and stimulatory effect of paraquat, which was abolished by the addition of superoxide dismutase, suggests that superoxide may promote NADPH-dependent lipid peroxidation in human placental mitochondria.     

Induction of Oxidative Stress in Roots of Oryza sativa L. in Response to Salt Stress

With the imposition of salt stress (0.5 to 3 % NaCl or CaCl₂) a decrease in germination rate and accumulation of proline was observed in the root tissue. Both NaCl and CaCl₂ solutions induced an increase in the total peroxide content and lipid peroxidation and decrease in catalase, guaiacol peroxidase and superoxide dismutase activities in root tissues suggesting an oxidative stress in the salt sensitive rice cultivar.     

The effect of modulators of free-radical oxidation on the functional activity of phagocytes

The influence of free-radical oxidation inhibitors (alpha tocopherol) and stimulators (levamisole and alriblastin) on the processes of the peroxide oxidation of lipids in blood serum and the phagocytic activity of peripheral blood neutrophils in Salmonella infection in rabbits at an early age is accompanied by phasic changes in the peroxide oxidation of lipids with activation at the early period of the development of the infection. The synchronism of changes in the peroxide oxidation of lipids and in the phagocytic activity of neutrophils is observed. Alpha tocopherol inhibits the peroxide oxidation of lipids and decreases the degree of the completeness of phagocytosis. Alriblastin stimulates the peroxide oxidation of lipids and increases the phagocytic activity of neutrophils.     

Cephaloridine-induced lipid peroxidation initiated by reactive oxygen species as a possible mechanism of cephaloridine nephrotoxicity

Rat kidney microsomes reduced cephaloridine when incubated anaerobically with NADPH. Superoxide anion was generated in a concentration- and time-dependent manner when cephaloridine was incubated with rat kidney microsomes. Cephaloridine increased the in vitro peroxidation of rat kidney microsomal lipids in a concentration- and time-dependent manner. Cephaloridine-induced lipid peroxidation was inhibited by a combination of superoxide dismutase and catalase, by the hydroxyl radical scavengers, mannitol, (+)-cyanidanol-3 and by the singlet oxygen scavenger histidine in a concentration-dependent manner. It is proposed that cephaloridine nephrotoxicity may occur through the transfer of an electron from reduced cephaloridine to oxygen and subsequent formation of the superoxide anion, hydrogen peroxide, the hydroxyl radical and singlet oxygen. These activated oxygen species then are very likely to react with membrane lipids to induce lipid peroxidation and nephrotoxicity.     

Inhibition of the Fenton reaction by the protein caeruloplasmin and other copper complexes. Assessment of ferroxidase and radical scavenging activities

The copper-containing protein caeruloplasmin is an important biological extracellular protein. By catalysing the oxidation of ferrous ions to the ferric state (ferroxidase activity) it can inhibit lipid peroxidation and the Fenton reaction. This activity is readily destroyed by heat-denaturation. When a ferric-EDTA complex is added to hydrogen peroxide, OH X radicals are formed in a reaction inhibitable by superoxide dismutase (SOD). This reaction is also inhibited by caeruloplasmin both before and after heat-denaturation, suggesting a non-catalytic scavenging role for the protein. A combination of ferroxidase and radical scavenging activities in fluids containing iron complexes and hydrogen peroxide, but no SOD or catalase, would make caeruloplasmin an important extracellular antioxidant.     

The effect of carnosine on indicators of free radical lipid oxidation during acute stress in rats

The effect of carnosine intraperitoneal injection in rats (in doses 0.2, 2.0 or 20 mg/kg) on the vegetative parameters (arterial blood pressure, Hildebrandt index), the content of free radical oxidation (FRO) products and superoxide dismutase activity in serum and brain homogenates and brain lipid composition under normal condition and after different stress forms have been investigated. The carnosine injection in dose 20 mg/kg preserves and increase in arterial pressure and Hildebrandt index at all steps of stress development. The phase non-unidirectional changes in studied biochemical parameters have been revealed depending on the level of stress development in animals under control. The unidirectional and dose-dependent changes of phospholipid content and the level of brain lipids, decrease of FRO products in tissue and brain cholesterol, the increase of the superoxide dismutase activity of serum and brain homogenates have been found in intact and stressed animals after carnosine injection. A comparison of carnosine pharmacokinetics with concentration dependences of the antioxidative effect under in vitro and in vivo experiments comes to conclusion concerning the carnosine indirect adaptogenic action.     

H2O2 but not $${\hbox{O}_{2}^{-}}$$ elevated by oxidized LDL enhances human aortic smooth muscle cell proliferation

The oxidation of low density lipoprotein (LDL) as a key event in atherosclerosis suggests that antioxidant interventions may reduce the risk of atherosclerosis. However, the better strategies among antioxidant remedies for atherosclerosis remains difficult to be determined. Here, we show that oxidized LDL increases the steady-state level of intracellular hydrogen peroxide through stimulating the protein expressions of Nox1 and Cu/Zn superoxide dismutase (SOD) in human aortic smooth muscle cells (SMCs). The intracellular content of hydrogen peroxide rather than superoxide is a key modulator for vascular SMC (VSMC) proliferation, implying that without co-expression of catalase, increased Cu/Zn-SOD activity alone may not be beneficial to reduce the growth of VSMC in an atherosclerotic plaque.     

Inhibition of erythrocyte superoxide dismutase by diethyldithiocarbamate also results in oxyhemoglobin-catalyzed glutathione depletion and methemoglobin production

N,N-Diethyldithiocarbamate (DDC), a copper-chelating agent, not only inhibits superoxide dismutase activity in the red cell, but also depletes glutathione and promotes the production of methemoglobin, sulfhemoglobin, and small amounts of lipid peroxidation products. DDC reacts with oxyhemoglobin to yield disulfiram, hydrogen peroxide, and methemoglobin. Disulfiram and hydrogen peroxide both convert GSH to GSSG, while DDC reduces methemoglobin to oxyhemoglobin. Although disulfiram also reacts with the hemoglobin sulfhydryl groups, this reaction does not play a role in the conversion of GSH to GSSG. Other hemoglobin derivatives, ferrous, and ferric ions do not catalyze the oxidation of GSH by DDC. These results support the conclusion that DDC reacts with the super-oxo-ferriheme complex of oxyhemoglobin to generate hydrogen peroxide and disulfiram and that the cyclic conversion of oxyhemoglobin to methemoglobin and DDC and disulfiram results in the net oxidation of GSH. Thus, damage to DDC-treated erythrocytes exposed to a putative superoxide-generating toxin, such as 1,4-naphthoquinone-2-sulfonate, may actually be due to diminished GSH concentration and hemoglobin oxidation rather than to superoxide radicals. Glucose added to the incubation medium of DDC-treated erythrocytes fully prevented glutathione depletion but not the oxidation of oxyhemoglobin to methemoglobin. Several other copper-chelating agents either failed to inhibit the activity of purified superoxide dismutase or when incubated with erythrocytes produced more extensive GSH depletion and hemoglobin oxidation than DDC. It is concluded that the interpretation of results with erythrocytes exposed to copper-chelating agents must consider their effects on GSH and hemoglobin as well as on superoxide dismutase inhibition. Moreover, one must be mindful of the interference by DDC in the analysis of GSH with 5,5'-dithiobis-(2-nitrobenzoic acid) in the absence of sufficient quantities of metaphosphoric acid to destroy DDC and that contamination of DDC with trace quantities of disulfiram may be a significant problem.