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Glutathione Ratio (glutathione + ratio)
Selected AbstractsEffects of dietary N -acetylcysteine on the oxidative stress induced in tilapia (Oreochromis Niloticus) exposed to a microcystin-producing cyanobacterial water bloom,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2009María Puerto Abstract Fish can be exposed to toxic cyanobacterial cells in natural waters and fish farms and suffer from oxidative damage. The present study investigates the effects of N-acetylcysteine (NAC), a glutathione (GSH) precursor, on the oxidative stress induced by Microcystis cyanobacterial cells containing microcystins (MCs) in tilapia fish (Oreochromis niloticus). Variation in lipid peroxidation (LPO) levels, carbonyl group content, reduced glutathione to oxidized glutathione ratio (GSH: GSSG), and catalase (Enzyme Commission [EC] 1.11.1.6), superoxide dismutase (SOD; EC 1.15.1.1), glutathione reductase (GR; EC 1.8.1.7), glutathione peroxidase (GPx; EC 1.11.1.9), and glutathione S-transferase (EC 2.5.1.18) activities in liver and kidney of tilapia exposed to a single oral dose of 120 ,g MC-LR (with leucine [L] and arginine [R])/fish and killed in 24 h were investigated in the absence and presence of 20.0, 44.0, and 96.8 mg NAC/fish/d. Results showed a protective role of NAC, depending on the dose and the biomarker considered. The increase in LPO (1.9-and 1.4-fold in liver and kidney, respectively) and the decreased protein content and GSH:GSSG in the liver induced by MCs were recovered mainly by the lower doses of NAC employed. Antioxidant enzyme activities increased (range, 1.4-to 1.7-fold) by MCs also were ameliorated by NAC, although the highest level used induced significant alteration of some enzymatic activities, such as SOD, GPx, and GR. Thus, NAC can be considered to be a useful chemoprotectant that reduces hepatic and renal oxidative stress in the prophylaxis and treatment of MC-related intoxications in fish when careful attention is given to its application dose because of its own pro-oxidant activity, as shown in the present study at 96.8 mg NAC/ fish/d. [source] Melatonin prevents oxidative stress and changes in antioxidant enzyme expression and activity in the liver of aging ratsJOURNAL OF PINEAL RESEARCH, Issue 3 2007José L. Mauriz Abstract:, This study compared the effects of melatonin supplementation on markers of oxidative stress, and on the activity and expression of antioxidant enzymes in the liver of young (3-month-old) and aging (24-month-old) rats. Animals were supplemented with melatonin in the drinking water (20 mg/L) for 4 wk. Liver concentration of thiobarbituric-reactive substances (TBARS), as an index of lipid peroxidation, and the oxidized to reduced glutathione ratio significantly increased in aged rats (+58%), while values did not significantly differ from the young in aged animals receiving melatonin. Significant decreases in the liver activities of Cu,Zn-superoxide dismutase (SOD) (,25%), cytosolic (,21%) and mitochondrial (,40%) glutathione peroxidase (GPx), and catalase (CAT) (,34%) were found in aged rats. Melatonin abolished these changes and also prevented the reduction of Cu,Zn-SOD (,33%), cytosolic GPx (,30%), and mitochondrial GPx (,47%) liver protein content as measured by Western blot. Reductions in Cu,Zn-SOD mRNA (,39%), and GPx mRNA (,86%) levels induced by aging were also abolished by melatonin. In summary, our data indicate that melatonin treatment abrogates oxidative stress in the liver of aged rats, and that prevention of the decreased activity of CAT and the downregulation of Cu,Zn-SOD and GPx gene expression contribute to this effect. [source] Melatonin inhibits the expression of the inducible isoform of nitric oxide synthase and nuclear factor kappa B activation in rat skeletal muscleJOURNAL OF PINEAL RESEARCH, Issue 1 2006María Alonso Abstract:, This study investigated whether the induction of inducible nitric oxide synthase (iNOS) produced by acute exercise in rat skeletal muscle could be prevented by melatonin and whether iNOS down-regulation was related to inhibition of nuclear factor kappaB (NF- ,B) activation. Male Wistar rats received melatonin i.p. at a dose of 1.0 mg/kg body weight 30 min before being exercised for 60 min on a treadmill at a speed of 25 m/min and a 10% slope. Exercise caused a significant induction of iNOS protein levels and a marked activation of NF- ,B that were significantly prevented in rats treated with melatonin. Exercise also resulted in increased I,B kinase, (IKK,) and phosphorylated I,B, protein levels, whereas I,B, content decreased. These effects were blocked by melatonin administration. The increase in the muscle concentration of thiobarbituric acid reactive substances and in the oxidized/reduced glutathione ratio induced by exercise was partially prevented by melatonin. Our data indicate that melatonin has potent protective effects against damage caused by acute exercise in rat muscle, preventing oxidative stress, NF- ,B activation and iNOS over-expression. These findings support the view that melatonin treatment, by abolishing the IKK/NF- ,B signal transduction pathway, might block the production of noxious mediators involved in the inflammatory process. [source] Oxidative Stress and Neutrophil Function in Cats with Chronic Renal FailureJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 3 2010R.F. Keegan Background: Oxidative stress is an important component in the progression of chronic renal failure (CRF) and neutrophil function may be impaired by oxidative stress. Hypothesis: Cats with CRF have increased oxidative stress and decreased neutrophil function compared with control cats. Animals: Twenty cats with previously diagnosed renal failure were compared with 10 age-matched control cats. Methods: A biochemical profile, CBC, urinalysis, antioxidant capacity, superoxide dismutase (SOD) enzyme activity, reduced to oxidized glutathione ratio (GSH : GSSG), and neutrophil phagocytosis and oxidative burst were measured. Statistical comparisons (2-tailed t -test) were reported as mean ± standard deviation. Results: The CRF cats had significantly higher serum blood urea nitrogen, creatinine, and phosphorus concentrations than control cats, and significantly lower PCV and urine specific gravity than control cats. The GSH : GSSG ratio was significantly higher in the CRF group (177.6 ± 197, 61.7 ± 33; P < .02) whereas the antioxidant capacity was significantly less in the CRF group (0.56 ± 0.21, 0.81 ± 0.13 Trolox units; P < .005). SOD activity was the same in control and CRF cats. Neutrophil oxidative burst after Escherichia coli phagocytosis, measured as an increase in mean fluorescence intensity, was significantly higher in CRF cats than controls (732 ± 253, 524 ± 54; P < .05). Conclusions: The higher GSH : GSSG ratio and lower antioxidant capacity in CRF cats is consistent with activation of antioxidant defense mechanisms. It remains to be determined if supplementation with antioxidants such as SOD beyond the level of control cats would be of benefit in cats with CRF. [source] Analysis of glutathione endpoints for measuring copper stress in Chlamydomonas reinhardthENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2007Tasha L. Stoiber Abstract Glutathione (GSH) is the most abundant nonprotein thiol in eukaryotic cells and it protects cells by functioning as an antioxidant and a metal-binding ligand. Because glutathione readily undergoes oxidation-reduction reactions to combat oxidative stress, intracellular ratios of the reduced (GSH) to the oxidized (GSSG) forms of glutathione may serve as an important biomarker of exposure and effect of trace metals in eukaryotic cells. We compared sensitivity of glutathione ratios in the freshwater alga Chlamydomonas reinhardtii to the traditional endpoints of cell growth rates and chlorophyll a following exposure to Cu for periods of 6 and 24 h. A response of the GSH:GSSG ratio to Cu concentration was observed at Cu levels of 40 and 80 nM after exposure for both 6 and 24 h. The concentration of total GSH at 24 h was roughly half the value at 6 h after exposure to either 40 or 80 nM Cu. A response for cell growth rate was observed only at 24 h, whereby the average specific growth rate decreased from about 1.1 to 0.4 d,1. The total Cu concentrations eliciting a cell response of 50%, effect concentrations (EC50s), after 24 h of exposure were similar (49.2, 49.8, and 38.2 nM Cu) and not significantly different for GSH:GSSG ratio, GSH levels, and specific growth, respectively. Total cell-associated Cu concentrations after exposure for 24 h were calculated from the EC50 endpoints and ranged from 13.3 to 17.0 fg/cell. Overall, thiol ratios were indicative of toxicity resulting from exposure to Cu, but precision may be greater for the cell growth rate endpoints. [source] | ||||||||||