Modulation Of Antioxidant Defense System Research Articles

Modulation of antioxidant defense system by the dithiocarbamate fungicides Maneb and Zineb in Chinese hamster V79 cells and the role of N-acetyl-L-cysteine

Oxidative stress is one of the major factors leading to Maneb- and Zineb-induced disorders. The aim of this in vitro study was to examine (i) the potency of Maneb and Zineb to induce changes in antioxidant enzyme activities in Chinese hamster fibroblasts V79 cells and (ii) the role of N-acetyl-L-cysteine (NAC) in the preventing their action. Maneb increased mitochondrial superoxide dismutase (SOD2) activity but failed to affect the activity of cytoplasmic superoxide dismutase (SOD1), whereas Zineb did not change the activity of any of superoxide dismutases. The activity of catalase (CAT) was reduced only by Zineb. The activity of both glutathione peroxidases (non-Se-GPx, Se-GPx) and glutathione reductase (GR) was decreased after exposure to these agents. After NAC pre-treatment Maneb increased the activity of GR, whereas the activity of non-Se-GPx was decreased as compared to that in NAC-treated cells. On the other hand, the activity of both SODs and CAT was decreased. Zineb decreased the activity of both GPxs and SOD2 with a concomitant increase in CAT activity comparing to NAC-treated cells. The results obtained thus suggest that Zineb acts by another mechanism, than Maneb does, and that one of the mechanisms of NAC protection against Maneb or Zineb-induced effects in V79 cells is its impact on enzymatic defense. Activity of GR, SOD2, and GPxs are the most affected enzymes.

Modulation of antioxidant defense system after long term arsenic exposure in Zantedeschia aethiopica and Anemopsis californica

Zantedeschia aethiopica (calla lily) and Anemopsis californica (yerba mansa) are plant species capable of accumulating arsenic (As) and therefore proposed as phytoremediation for removal of As from drinking water. The effects of a continuous 6 month As exposure (34±11μg/L) from local contaminated groundwater on the antioxidant response of Z. aethiopica and A. californica were evaluated in leaves and stems of the plants bimonthly in a subsurface flow constructed wetland. As increased the activities of the antioxidant enzymes ascorbate peroxidase, glutathione reductase and catalase where higher levels were observed in Z. aethiopica than A. californica. No significant differences were detected on lipid peroxidation levels or antioxidant capacity evaluated by ORAC and DPPH assays or total phenol contents in any part of the plant, although in general the leaves of both plants showed the best antioxidant defense against the metal. In conclusion, Z. aethiopica and A. californica were able to cope to As through induction of a more sensitive enzymatic antioxidant response mechanism.

SU‐E‐T‐20: Differential Modulation of Antioxidant Defense System in Various Organs of Balb/c Mice by Whole Body Exposure to Low‐Dose Gamma Radiation

Purpose: To evaluate the effect of low‐dose (< 50 cGy) whole body gamma irradiation on antioxidant defense system enzymes in the liver, lung and kidney of Balb/c mice at various post‐irradiation intervals. We examined the critical level of radiation dose and the degree to which these changes remain affected in these organs after irradiation. Methods: Young male Balb/c mice (5–6 wks), were divided into irradiated and non‐irradiated groups. Whole body irradiation was done with gamma rays from a, 60</sup> Cobalt source at doses of 10, 25 and 50 cGy (48.78 cGy/min). Lipid peroxidation and antioxidant defense enzymes (reduced glutathione, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase) were measured in liver, lung and kidney at 4, 12 and 24 hr after irradiation.Results: Lipid peroxidation increased by 1.38, 2.0 and 1.33 folds in lung, liver and kidney respectively at 12 hrs after exposure to 25 cGy. Reduced glutathione increased significantly in all these organs at 12 hrs after exposure of the animals at these doses as compared to control. Superoxide dismutase activity increased in liver and kidney up to 1.37 folds at 12 hrs of exposure at these doses. The antioxidant enzyme activities of catalase, glutathione peroxidase and glutathione reductase also increased between 1.1 and 1.3 folds in kidney and liver of mice at these doses. Interestingly, the activities of these enzymes remained unaltered in the lung after exposure of the animals at different doses Conclusions: Low‐dose whole body irradiation differentially modulates the antioxidant defense system in liver, lungs and kidneys of mice which may be due to variable sensitivities in activation of the related genes in these organs. The induction of endogenous glutathione immediately after exposure to low‐dose gamma irradiation, may be beneficial in protecting the cells from the reactive oxygen species (ROS) induced oxidative stress in various ROS‐related diseasesFunds for conducting this project were provided by Director, Post Graduate Institute of Medical Education and Research, Chandigarh, India.

Effects of Cadmium, Chromium and Lead on Growth, Metal Uptake and Antioxidative Capacity in Typha angustifolia

This study investigates the modulation of antioxidant defence system of Typha angustifolia after 30 days exposure of 1 mM chromium (Cr), cadmium (Cd), or lead (Pb). T. angustifolia showed high tolerance to heavy metal toxicity with no visual toxic symptom when exposed to metal stress, and Cd/Pb addition also increased plant height and biomass especially in Pb treatment. Along with increased Cr, Cd, and Pb uptake in metal treatments, there was enhanced uptake of plant nutrients including Ca and Fe, and Zn in Pb treatment. A significant increase in malondialdehyde (MDA) content and superoxide dismutase (SOD) and peroxidase (POD) activities were recorded in plants subjected to Cr, Cd, or Pb stress. Furthermore, Pb stress also improved catalase (CAT), ascorbate peroxidase (APX), and glutathione peroxidase (GPX) activities; whereas Cr stress depressed APX and GPX. The results indicate that enzymatic antioxidants and Ca/Fe uptake were important for heavy metal detoxification in T. angustifolia, stimulated antioxidative enzymes, and Ca, Fe, and Zn uptake could partially explain its hyper-Pb tolerance.

Modulation of antioxidant defence system in brain of rainbow trout ( Oncorhynchus mykiss) after chronic carbamazepine treatment

We investigated the effect of long-term exposure to CBZ on the antioxidant system in brain tissue of rainbow trout. Fish were exposed to sublethal concentrations of CBZ (1.0 μg/L, 0.2 mg/L or 2.0 mg/L) for 7, 21, and 42 days. Oxidative stress indices (LPO and CP) and activities of antioxidant enzymes (SOD, CAT, GPx and GR) in fish brain were measured. In addition, non-enzymatic antioxidant (GSH) was determined after 42 days exposure. Carbamazepine exposure at 0.2 mg/L led to significant increases ( p < 0.05) of LPO and CP after 42 days and, at 2.0 mg/L, after 21 days. Activities of the antioxidant enzymes SOD, CAT, and GPx in CBZ-treated groups slightly increased during the first period (7 days). However, activities of all measured antioxidant enzymes were significantly inhibited ( p < 0.05) at 0.2 mg/L exposure after 42 days and after 21 days at 2.0 mg/L. After 42 days, the content of GSH in fish brain was significantly lower ( p < 0.05) in groups exposed to CBZ at 0.2 mg/L and 2.0 mg/L than in other groups. Prolonged exposure to CBZ resulted in excess reactive oxygen species formation, finally resulting in oxidative damage to lipids and proteins and inhibited antioxidant capacities in fish brain. In short, a low level of oxidative stress could induce the adaptive responses of antioxidant enzymes, but long-term exposure to CBZ could lead to serious oxidative damage in fish brain.

Modulation of antioxidant defence system for arsenic detoxification in Indian mustard

This study investigates the modulation of antioxidant defence system of Indian mustard (cv. Pusa Jai Kisan) against the arsenic (As)-induced toxicity in 20-day-old plants, exposed to 5 and 25 μM As for 96 h in hydroponic culture. Reduction in plant growth, measured in terms of root and shoot dry weights, was insignificant with 5 μM, but highly significant with 25 μM As treatment. Shoots accumulated more As than roots. The extent of oxidative stress in the leaves was measured as the rate of lipid peroxidation. The As treatments significantly increased the activities of antioxidative enzymes (superoxide dismutase, ascorbate peroxidase and glutathione reductase) and the contents of antioxidants metabolites (glutathione and ascorbate), the increase being dependent on exposure time. Increase in the activity of catalase was not significant, however. In conclusion, Indian mustard was able to detoxify the low As level through induction of antioxidant defence mechanism.

Modulation of antioxidant defense system by the environmental fungicide carbendazim in Leydig cells of rats

Carbendazim (methyl-2-benzimidazole carbamate, MBC) a metabolite of benomyl is one of the most widespread environmental contaminant of major concern to human and animal reproductive health. The present investigation was undertaken to study the impact of carbendazim exposure on Leydig cell functions. Adult albino male rats of the Wistar strain were administered with carbendazim (25 mg/(kg (body weight)/day)) orally for 48 days. The control animals received vehicle (corn oil) alone. Another group of rats were treated with carbendazim and the same was withdrawn for a further period of 48 days. After the treatment period, rats were euthanized and blood was collected for the assay of serum hormones such as luteinizing hormone (LH), prolactin (PRL), testosterone and estradiol. Testes were immediately removed and Leydig cells were isolated in aseptic condition. Purified Leydig cells were used for quantification of steroidogenic enzymes such as 3β-hydroxysteroid dehydrogenase (3β-HSD) and 17β-hydroxysteroid dehydrogenase (17β-HSD). Leydig cellular enzymatic antioxidants superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione- S-transferase (GST), γ-glutamyl transpeptidase (γ-GT), glucose-6-phosphate dehydrogenase (G6PDH) and non-enzymatic antioxidants such as reduced glutathione (GSH), α-tocopherol (vitamin E), ascorbic acid (vitamin C) and β-carotene (vitamin A) were assayed. Lipid peroxidation (LPO) and reactive oxygen species (ROS) were also quantified. Carbendazim exposure had no effect on body weight, serum LH and prolactin. However, testis weight, serum testosterone and estradiol were significantly decreased. In addition to this, Leydig cellular activities of steroidogenic enzymes such as 3β-HSD, 17β-HSD, antioxidant enzymes SOD, CAT, GPx, GR, GST, γ-GT, G-6-PDH and non-enzymatic antioxidants such as GSH, vitamins E, C and A were significantly diminished, whereas LPO and ROS were markedly elevated. All these above-mentioned parameters from the animals after withdrawal of MBC treatment were similar to those of the control group. Thus, the present study suggests that chronic low dose treatment of MBC is capable of inducing reproductive toxicity through increased oxidative stress, but is transient and reversible upon withdrawal of treatment.

Markers of inflammation and oxidative stress in patients undergoing CABG with CPB with and without ventilation of the lungs: a pilot study

Cardiopulmonary bypass triggers systemic inflammation and systemic oxidative stress. Recent reports suggest that continuous ventilation during cardiopulmonary bypass (CPB) can affect the outcome of patients after cardiac surgery. We investigated the influence of lung ventilation on inflammatory and oxidative stress markers during coronary artery bypass graft (CABG) with CPB in 13 patients with (Group 2) or without (Group 1) ventilation of the lungs with small tidal volume (4 ml/kg). IL-10 and elastase in blood were elevated in both groups with a peak at the end of CPB (P<0.05) and returned to the baseline at 24 h after surgery. A significant increase in Trolox Equivalent Antioxidant Capacity (TEAC) was observed in both groups (P<0.05). Glutathione peroxidase (GPx) was significantly elevated 24 h after surgery only in Group 1 (P<0.05). There was a significant decrease in alpha-tocopherol 24 h after surgery in both groups (P<0.05). The inflammatory response observed during CPB is not directly influenced by continuous ventilation of the lungs with small tidal volumes. The modulation of antioxidant defense systems by ventilation needs further investigation.

Radioprotective Effect of Ginsan through Stimulating the Hematopoiesis and Modulating Antioxidant Enzymes

An immunomodulator ginsan, polysaccharide isolated from Panax ginseng, showed a mitogenic activity, generation of LAK cells, and the secretion of several cytokines. In the present study, we evaluated the protective effects of in vivo injected ginsan against irradiation. Ginsan was found to significantly increase the number of bone marrow cells, spleen cells and the number of circulating neutrophils, lymphocytes and platelets in irradiated mice. In addition, ginsan induced the production of a variety of cytokines such as IL-1, IL-6, IL-12, TNF-a and SCF, which are required for a hematopoietic recovery and are closely correlated with the antioxidant defense systems. We demonstrated that the pretreatment with ginsan protected the mice from the lethal effects of ionizing radiation more effectively than given after the irradiation. A dramatic increase of the survival of the ginsan-treated group from LD50/30 7.54 Gy of the PBS-control group to 10.93 Gy was observed. Moreover, the levels of the antioxidant enzymes such as superoxide dismutase (SOD), catalase and gluthathion peroxidase (GPx) were increased 1.5-2 fold in the ginsan treated mice compared to the irradiated mice. In conclusion, our data suggests that the radioprotective action of ginsan in the irradiated mice may be due to not only to the rapid regeneration of hematopoietic cells but also to the modulation of antioxidant defense systems.

Modulation of Antioxidant Defense Systems by the Environmental Pesticide Maneb in Dopaminergic Cells

A lack of evidence supporting a role of heritability in the development of idiopathic Parkinson’s disease (PD) has implicated exposures to environmental contaminants in the disease etiology. Epidemiological and clinical studies, as well as animal models of the PD phenotype, have consistently linked agrichemical exposure with dopaminergic (DAergic) damage, particularly through oxidative stress mechanisms. Maneb (MB) is a dithiocarbamate (DTC) fungicide that has specifically been implicated to have adverse effects on dopamine (DA) systems, but the role MB plays in modulating the oxidative state of DAergic cells has not previously been described. Since glutathione (GSH) is a major cellular antioxidant, it was hypothesized that exposure to MB would disrupt this system. The current study primarily utilized the PC12 cell line, which displays a catecholaminergic phenotype. Low concentrations of MB (50–1000 ng/ml) had little effect on cell viability, as measured by LDH release. These same concentrations, however, led to increases in GSH and its oxidized form, GSSG. Effects on viability and GSH were correlated to a primary mesencephalic culture system. Furthermore, these effects were markedly different from those observed with the classical oxidative stressor and pesticide, paraquat (PQ). To determine how MB would affect cells in which antioxidant systems were compromised, PC12 cells were treated with l-buthionine-( S, R)-sulfoximine (BSO) to deplete cellular GSH, followed by treatment with MB. Results suggest that following an insult to the GSH antioxidant system, MB can act as an additional insult to the system and prevent the normal recovery of those defenses. Altered protein levels of heme oxygenase-1 (HO-1) further indicated an oxidative stress response elicited by MB in PC12 cells. DAergic neurons, as a population, are inherently vulnerable to oxidative stress, and the disruption of antioxidant systems by the fungicide MB may contribute to the neurodegeneration of these cells, especially with concurrent exposures to other environmentally relevant oxidative stressors, such as PQ.

Oxidant/Antioxidant status in relation to thyroid hormone metabolism in selenium‐ and/or iodine‐deficient rats

AbstractIodine and selenium are essential components of normal thyroid hormone metabolism and are involved in the modulation of antioxidant defense system. This study was designed to evaluate the extent of peroxidation of lipids and activities of antioxidant enzymes (AOEs) in various tissues of iodine‐ and/or selenium‐deficient rats in relation to thyroid hormone metabolism. Iodine deficiency caused marked enhancements in glutathione peroxidase (GSHPx), superoxide dismutase (SOD), and catalase (CAT) activities in thyroid but did not cause lipid peroxidation (LP), indicating the occurrence of an adaptive response that protected the gland against oxidative stress induced by high levels of thyroid stimulating hormone (TSH). Except significant reduction in CAT activity in liver and kidney and an enhancement of SOD in kidney, iodine deficiency did not cause any other alterations in other tissues. Selenium deficiency and combined iodine and selenium deficiency caused significant alterations in AOE activities in all tissues and caused significantly high levels of LP in thyroid, liver, brain, and plasma, but not in kidney. Alterations in selenium‐involved deficiencies appeared to be mainly caused by substantial losses of GSHPx activity; however, compensatory changes in SOD and CAT activities were also observed. J. Trace Elem. Exp. Med. 17:109–121, 2004. © 2004 Wiley‐Liss, Inc.

Modulation of antioxidant defence system by dietary fat in rats intoxicated with o-toluidine.

o-Toluidine was administered to rats in the diet for four weeks at levels approximately 40, 80 and 160 mg/kg b.w. per day. Two types of diet have been used, standard (4% fat) and high fat (14% fat). Activity of antioxidant enzymes, level of glutathione and thiobarbituric acid reactive substances were measured in liver. Glutathione peroxidase was significantly increased in all treated groups while glutathione S-transferase and glutathione reductase were elevated in rats fed high-fat diet. o-Toluidine slightly enhanced catalase activity regardless of the kind of diet. Superoxide dismutase was the only enzyme whose activity was lowered in almost all treated groups. Enzymatic and nonenzymatic microsomal lipid peroxidation was enhanced 2- to 3-fold in both diet groups. Reduced glutathione level in liver was 2.3- to 4.0-fold increased in all treated groups. Our findings indicate that free radical processes can be involved in the toxic effects of o-toluidine and dietary fat can modify the response of some antioxidant enzymes to this compound.

Defective antioxidant defense system in patients with a human leptin gene mutation.

Antioxidant defense system prevents the organism from the detrimental effects of free radicals via scavenging or inhibiting their formation. Changes in the antioxidant defense mechanisms and alterations of several essential trace elements in both plasma and various tissues of ob/ob mice have been reported previously. Recent finding of the restoration of the defective antioxidant enzyme activity after leptin treatment in ob/ob mice suggests a putative role of leptin in modulation of antioxidant enzyme activity. Therefore, the aim of this study was to investigate whether antioxidant enzymes and trace elements could also be altered in patients with leptin gene mutation. Seven patients (five men and two women, two of them are homozygous and 5 are heterozygous) with leptin gene mutation and 31 healthy, sex- and age-matched and non-related to the patients (24 male and 9 female), control volunteers were enrolled in the study. Plasma and erythrocyte glutathione peroxidase (GSH-Px) and erythrocyte copper-zinc superoxide dismutase (CuZn-SOD) activities were measured spectrophotometrically. Plasma selenium (Se), manganese (Mn), zinc (Zn), copper (Cu), and iron (Fe) levels were measured by atomic absorption spectrophotometry. Mean Cu and Fe levels in patients were not significantly different than those in controls whereas mean Se, Zn and Mn levels were significantly lower in patients than those of controls (P=0.007, P=0.001, and P=0.001, respectively). Erythrocyte GSH-Px (39%), plasma GSH-Px (24%) and erythrocyte CuZn-SOD activities (32%) were significantly lower than those of the control group (P=0.001, P=0.002, P=0.001, respectively). In conclusion, our results demonstrate that the activity of antioxidant enzymes and plasma levels of Se, Zn and Mn levels were decreased in both homozygous and heterozygous subjects with leptin gene mutation. We suggest that both leptin and trace elements might be involved in the modulation of antioxidant defense system.