Glutathione Peroxidase Activity In Muscle Research Articles

Dietary supplementation with nerolidol improves the antioxidant capacity and muscle fatty acid profile of Brycon amazonicus exposed to acute heat stress.

An increase in water temperature in the Amazon River has elicited concerns about commercially important fish species associated with food security, such as matrinxã (Brycon amazonicus). Studies have demonstrated the positive effects of diets supplemented with plant-based products that combat heat stress-induced oxidative damage. The aim of this study was to determine whether dietary supplementation with nerolidol prevents or reduces muscle oxidative damage and impairment of the fillet fatty acid profile of matrinxã exposed to heat stress. Plasma and muscle reactive oxygen species (ROS) and lipid peroxidation (LPO) levels were significantly higher in fish exposed to heat stress compared to fish not exposed to heat stress, while plasma superoxide dismutase (SOD) and glutathione peroxidase (GPx) activity was significantly lower. The total content of saturated fatty acids (SFA) in fillets was significantly higher in fish exposed to heat stress compared to fish not exposed to heat stress, while he total content of polyunsaturated fatty acids (PUFA) was significantly lower. Nerolidol prevented the increase of muscle LPO and plasma ROS and LPO levels in fish exposed to heat stress, and partially prevented the increase in muscle ROS levels. Diets containing nerolidol prevented the inhibition of muscle GPx activity in fish exposed to heat stress, and partially prevented the decrease of plasma GPx activity. The nerolidol-supplemented diet prevented the increase of fillet SFA in fish exposed to heat stress, while partially preventing the decrease of PUFA. We conclude that acute heat stress at 34°C for 72h causes plasma and muscular oxidative damage, and that homeoviscous adaptation to maintain membrane fluidity can represent a negative impact for fish consumers. A nerolidol diet can be considered a strategy to prevent heat stress-induced oxidative damage and impairment of muscle fatty acid profiles.

Complexed trace mineral supplementation alters antioxidant activities and expression in response to trailer stress in yearling horses in training

To test the hypothesis that complexed trace mineral supplementation would increase antioxidant capacity and decrease muscle oxidative stress and damage in young horses entering an exercise training program, Quarter Horses (mean pm SD; 9.7 ± 0.7 mo) balanced by age, sex, and BW were assigned to receive complexed (CTM; n = 8) or inorganic (INORG; n = 8) trace minerals at -12 week relative to this study. Blood and muscle samples were collected before (week 0) and after 12 week of light exercise training surrounding a 1.5-h trailer stressor. Muscle glutathione peroxidase (GPx) activity was higher for CTM than INORG horses (P ≤ 0.0003) throughout the study. Following both trailer stressors, serum creatine kinase increased (P < 0.0001) and remained elevated through 24 h post-trailering (P < 0.0001). At week 0, muscle malondialdehyde, expression of superoxide dismutase 2, and whole blood GPx activity increased (Ple 0.003) following trailering but trailering did not affect these measures at week 12. Young horses supplemented with CTM had higher muscle GPx activity than horses receiving INORG, but CTM did not affect damage markers following a stressor. Dietary CTM may be useful for improving antioxidant capacity during exercise training in young equine athletes.

Controlled expression of the migratory phenotype affects oxidative status in birds.

High caloric intake can increase production of reactive oxygen and nitrogen species. We examined whether the emergence of the migratory phenotype, primarily signalled by increased food intake and fuelling, is accompanied by changes in oxidative status. We induced autumn migration followed by a non-migratory wintering phase in common quails (Coturnix coturnix). We compared three markers of oxidative status - oxidative damage to lipids expressed as thiobarbituric acid reactive substances (TBARS); superoxide dismutase (SOD); and glutathione peroxidase (GPx) - between birds sampled during the migratory and non-migratory phase. We found that the emergence of the migratory phenotype was associated with: (i) higher levels of TBARS in the liver; (ii) lower levels of SOD in red blood cells and, marginally, in the liver; (iii) higher levels of GPx in the pectoral muscle; and (iv) sex-specific changes in red blood cells and liver. We found no link between food intake and variation in markers of oxidative status in any of the tissues examined, despite food intake being higher in the migratory birds. However, the increase in body mass was positively correlated with muscle GPx activity as birds entered the pre-migratory fattening phase, while the amount of decrease in body mass was negatively correlated with muscle GPx as birds transitioned to the non-migratory phase. Such correlations were absent in red blood cells and liver. Our work suggests that during the emergence of the migratory phenotype, birds might strategically displace oxidative costs on the liver in order to safeguard the pectoral muscles, which have a fundamental role in successfully completing the migratory flight.

The Oxidative Stress Markers in the Erythrocytes and Heart Muscle of Obese Rats: Relate to a High-Fat Diet but Not to DJOS Bariatric Surgery.

Obesity and high-fat diet (HF) are prevalent causes of oxidative stress (OS). Duodenal-jejunal omega switch (DJOS) is a bariatric procedure used for body mass reduction, extensively tested in animal models. We studied the long-term impact of bariatric surgery and an HF diet on the oxidative stress markers in erythrocytes and heart muscles of rats. We analyzed superoxide dismutase (SOD), catalase (CAT), glutathione transferase (GST), glutathione reductase (GR), glutathione peroxidase (GPx) activity and malondialdehyde (MDA) concentration in DJOS or SHAM (control) operated rats fed with different dietary protocols (control diet (CD) and high-fat diet (HF)), before and after the surgery (CD/CD, HF/HF, CD/HF, and HF/CD). We observed higher erythrocytes CAT, GST and GPx activity in DJOS-operated (vs. SHAM) rats fed with an HF/HF diet. For DJOS-operated rats, erythrocytes CAT and GPx activity and MDA concentration were significantly lower in CD/CD group. We observed increased heart muscle GR activity in SHAM-operated rats (vs. DJOS bariatric surgery) fed with an HF/HF diet. Change from HF to CD diet increased heart muscle GPx activity after DJOS bariatric surgery. Heart muscle SOD activity was lower in HF/HF and CD/CD groups after DJOS bariatric surgery (vs. SHAM). DJOS surgery significantly reduced heart muscle MDA concentration in HF/HF and HF/CD groups (vs. SHAM). We conclude that the selected dietary patterns had a stronger impact on oxidative stress markers in erythrocytes and heart muscle than DJOS bariatric surgery.

Effects of increasing temperature on antioxidant defense system and oxidative stress parameters in the Antarctic fish Notothenia coriiceps and Notothenia rossii

Antioxidant defense system (ADS) and oxidative stress parameters were evaluated in the Antarctic fish Notothenia rossii and N. coriiceps exposed to increasing temperature. Acclimated fish were kept at 0°C or exposed to 4°C for 1day (N. rossii) or to 2 and 4°C for 1 and 6 days (N. coriiceps). Measurements were assessed in brain, gills, liver, white muscle and erythrocytes. Parameters analyzed included antioxidant capacity against peroxyl radicals (ACAP); reduced glutathione (GSH) and metallothionein-like proteins (MTLP) concentration; superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST) and glutamate-cysteine ligase (GCL) activity; lipid peroxidation (LPO) level and protein carbonyl (PC) concentration. Increased liver GST activity was observed in N. rossii exposed to 4°C for 1day. Increased muscle GPx activity was observed in N. coriiceps after exposure to 2°C for 1day. Reduced gill GPx activity and increased liver SOD activity were observed after exposure to 4°C for 1day. In N. coriiceps, increased gill GCL activity and reduced gill GPx activity, as well as reduced liver MTLP were observed after exposure to 2°C for 6 days. Reduced brain SOD activity and increased brain LPO; reduced gill ACAP, GSH concentration and GPx activity, as well as increased gill GCL activity; reduced liver ACAP, MTLP, SOD activity, GST activity and increased liver and erythrocytes LPO were observed after exposure to 4°C for 6 days. These findings indicate that ADS is more responsive to short-term increasing temperature in the sluggish N. coriiceps than in the active N. rossii. However, responses of N. coriiceps to long-term increasing temperature were transient and did not prevent tissue oxidative damage. Considering the predicted increase in temperature in the Southern Ocean over the next decades, our findings suggest that Antarctic fishes are sensitive to ocean warming, displaying tissue oxidative damage associated with the thermal stress.

Effect effects of &lt;i&gt;Auricularia auricula&lt;/i&gt; polysaccharides on exhaustive swimming exercise-induced oxidative stress in mice

Purpose: To determine the effects of polysaccharides from Auricularia auricula (AAPs) on exerciseinduced oxidative stress in mice.Methods: The animals were divided into four groups: control (C), low, middle, and high-dose AAPstreated (LA, MA, and HA, respectively). C group received physiological saline solution while AAPstreated groups received different doses of AAPs (50, 100, and 200 mg/kg) via oral gavage once a day for 28 days, followed by an exhaustive swimming exercise. Swimming times were recorded for each animal after which malondialdehyde (MDA), 8-hydroxydeoxyguanosine (8-OHdG), superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) were determined.Results: Exhaustive swimming times were significantly prolonged in all AAPs-treated animals as compared with controls. In all treatment groups, serum and muscle MDA levels were significantly lower than those in the C group, whereas in the MA- and HA-treated groups, a decrease was also seen for liver MDA levels. Furthermore, the concentration of 8-OHdG was significantly reduced in serum, liver, and muscle in all AAPs-treated animals. In contrast, all AAPs treatment groups exhibited significantly higher SOD activity in serum, liver, and muscle. Serum and liver GPx activity was also significantly increased in all animals receiving AAPs treatment, with MA- and HA-treated mice exhibiting an additional augmented GPx activity in muscle. Serum and liver catalase activities in the MA and HAtreated groups, and catalase activity in muscle in all AAPs treatment cohorts, were significantly higher.Conclusion: Polysaccharides from Auricularia auricula enhance exercise endurance and possess protective effects against exhaustive swimming exercise-induced oxidative stress in mice.Keywords: Exhaustive swimming, Malondialdehyde, 8-Hydroxydeoxyguanosine, Superoxide dismutase, Glutathione peroxidase, Catalase

Effects of Dietary Selenium and Training on Oxidative Stress in Young Horses

IntroductionExercise training can enhance antioxidant status, but it is unknown whether selenium supplementation can further improve antioxidant defenses.MethodsAmerican Quarter Horse yearlings (n = 20; mean ± SE 18 ± 0.2 months) balanced with regard to age and sex were randomly assigned to four dietary Se and training treatments for 14 weeks: 0.1 mg Se/kg DM with (n = 5) or without (n = 5) training or 0.3 mg Se/kg DM with (n = 5) or without (n = 5) training. Trained horses were exercised 4 d/wk for 30 min/d. At wk 14, all horses underwent a 2‐hr, 27.5 km submaximal exercise test (SET). Blood samples and biopsies of the gluteus medius were obtained before and after training and in response to the SET. Serum Se, glutathione peroxidase (GPx) activity in whole blood and muscle, and plasma lipid hydroperoxides (LPO) were evaluated. Data were analysed using a mixed model ANOVA with repeated measures.ResultsSerum Se was higher (P = 0.02) at wk 14 in trained horses receiving 0.3 than 0.1 mg Se/kg, but was unaffected by diet in untrained horses. Muscle GPx activity was unchanged after 14‐weeks of Se and training, but in response to the SET, muscle GPx was higher (P = 0.05) in trained than untrained horses. An effect of training*time (P = 0.008) was noted for whole blood GPx, reflecting greater (P = 0.01) activity in trained than untrained horses immediately after the SET. Plasma LPO was not influenced by dietary Se, but increased (P&lt;0.0001) in untrained horses immediately after the SET while remaining unchanged in trained horses.ConclusionsTraining appears to mitigate oxidative damage in response to prolonged exercise in young horses. Although trained horses responded to a higher level of dietary Se, it showed no clear advantage for reducing oxidative stress.Ethical Animal ResearchThis project was approved by the Institute of Food and Agricultural Sciences Animal Care Committee at the University of Florida (approval number 016‐12ANS). Sources of funding: Partial financial support of this project was provided by Alltech, Nicholasville, KY, USA. Competing interests: none.

Effects of nano-selenium on performance, meat quality, immune function, oxidation resistance, and tissue selenium content in broilers

This study was conducted to investigate the effect of nano-selenium (nano-Se) on performance, meat quality, immune function, oxidation resistance, and tissue selenium content in broilers. A total of five hundred forty 1-d-old male Arbor Acres broilers were randomly allotted to 1 of 5 treatments with each treatment being applied to 6 replicates of 18 chicks. The 5 treatments consisted of corn-soybean meal-based diets supplemented with 0.0, 0.3, 0.5, 1.0, or 2.0 mg/kg of nano-Se. The selenium content of the unsupplemented control diet was 0.09 mg/kg for the starter phase (0 to 21 d) and 0.08 mg/kg for the grower phase (22 to 42 d). There were no significant differences (P > 0.05) in performance, meat color, or immune organ index (thymus, bursa, and spleen) due to supplementation with nano-Se. On d 42, a significant quadratic effect of nano-Se was observed on glutathione peroxidase activity, free radical inhibition, contents of IgM, glutathione, and malondialdehyde in serum, on glutathione peroxidase activity, free radical inhibition in liver, and on glutathione peroxidase activity in muscle, with birds fed 0.30 mg/kg of nano-Se exhibiting the best effect and birds fed 2.0 mg/kg of nano-Se showing the worst effect on these parameters. Liver and muscle selenium content increased linearly and quadratically as the dietary nano-Se level increased (P < 0.01), and reached the highest value when 2.0 mg/kg of nano-Se was fed. Based on a consideration of all experiment indexes, 0.3 to 0.5 mg/kg is suggested to be the optimum level of supplementation of nano-Se, and the maximum supplementation of nano-Se could not be more than 1.0 mg/kg in broilers.

Alcoholic Myopathy: Vitamin D Deficiency is Related to Muscle Fibre Atrophy in a Murine Model

Chronic myopathy has been described in alcoholics, characterized by atrophy of type II fibres, and vitamin D deficiency. Low serum vitamin D levels are frequent in alcoholics. The possibility exists that serum vitamin D levels are related to muscle changes in a murine experimental model. Histological analysis of the right gastrocnemius muscle was performed in four groups of adult Sprague-Dawley rats, sacrificed after 5 weeks of treatment following the Lieber-DeCarli model. We studied the association between muscle histological changes and the activity of glutathione peroxidase (GPX), superoxide dismutase (SOD) and lipid peroxidation products (malondialdehyde); parathyroid hormone (PTH), insulin-like growth factor 1 (IGF-1), free testosterone, 1,25 dihydroxyvitamin D3 (vitamin D) and corticosterone; and serum calcium and magnesium. Alcoholic animals showed type IIa and IIb fibre atrophy, especially the low-protein-fed ones, an effect dependent on protein deficiency. A significant relationship was observed between serum vitamin D levels and IIa fibre area (rho = 0.56, P = 0.002), and also, as a trend, between vitamin D and type IIb fibre area (rho = 0.39, p = 0.053); between vitamin D and muscle GPX (rho = 0.40, P = 0.025) and SOD activities (rho = 0.43, P = 0.012). Muscle GPX activity was significantly related with type I fibre area (rho = 0.49, P = 0.01) and muscle SOD, with type IIa fibre area (rho = 0.38, P = 0.045). Serum testosterone was also related with type IIa fibre area (rho = 0.61, P < 0.001). No relation was observed between serum PTH, corticosterone, or IGF-1 and fibre area PTH and antioxidant systems. Multiple regression analysis disclosed that the only parameter independently related with type IIa fibre area was serum vitamin D. Low vitamin D levels are related to muscle fibre atrophy, and altered levels of muscle antioxidant enzymes could play a role in alcoholic myopathy.

Effect of diet finishing mode (pasture or mixed diet) on antioxidant status of Charolais bovine meat

The aim of this study was to better understand the effect of diet finishing mode (pasture or mixed diet) on the antioxidant status of bovine meat ( M. Longissimus dorsi). Effects of sex (cow, heifer and steer) and age (only in cows) were also studied. Vitamin E content of muscle and activity of antioxidant enzymes, such as superoxide dismutase (SOD), catalase (Cat) and glutathione peroxidase (GPx), were measured. Total antioxidant status was also estimated by measuring Trolox equivalent antioxidant capacity (TEAC) and benzoate hydroxylation. Vitamin E content was higher in meat from pasture-finished animals than from mixed diet-finished animals. Diet had also an important effect on antioxidant enzyme activity. Pasture finishing mode increased SOD activity and decreased GPx activity in muscle. Effect of diet on catalase activity was less pronounced. Total antioxidant status measured by benzoate hydroxylation was higher in the mixed diet-group but no effect of diet was observed on TEAC measurement. Effect of sex was observed on SOD and catalase activity and also in benzoate hydroxylation. Effect of age was only noticed on benzoate hydroxylation.

Glutathione peroxidase activity and selenoprotein W levels in different brain regions of selenium-depleted rats

Previous studies in selenium (Se)-depleted sheep and rats showed that selenoprotein W (SeW) levels decreased in all tissues except brain. To further investigate this depletion in different parts of the brain, second generation Se-depleted rats were used. Dams consumed a Se-deficient basal diet during gestation and lactation, and deficient rats were obtained by continuation on the same diet. Control rats were fed a diet with 0.1-mg Se/kg diet after weaning. Glutathione peroxidase (GPX) activities were measured for comparative purposes to SeW levels. GPX activity in muscle, skin, spleen, and testis increased about 4-fold with Se repletion and reached a plateau after 6 or 10 weeks, but GPX activity decreased to almost one tenth of the original activity with continuous Se depletion. In contrast, GPX activities increased, rather than declined, in various brain regions (cortex, cerebellum, and thalamus) with time of feeding the deficient diet. An experiment with first generation rats, however, indicated that GPX activity was significantly lower in these three brain regions from rats fed the deficient diet as compared to rats fed the supplemented diet. SeW levels in skin, spleen, muscle, and testis were undetectable in weanling rats, but became detectable after 6 weeks of Se repletion. In contrast, the expression of SeW in cortex, cerebellum, and thalamus was not significantly affected by Se depletion, but increased SeW levels occurred only in thalamus with Se supplementation. The results with GPX using first and second generation rats suggest that there are “mobile” and “immobile” GPX fractions in the brain.

Effects of dietary supplementation with vitamin E and organic selenium on the oxidative stability of beef.

The effects of supplementation of beef cattle diets with organic Se (0.3 mg/kg) and vitamin E (300 I.U. alpha-tocopheryl acetate/kg feed), for 55 d preceding slaughter, on the antioxidant status and oxidative stability of muscle was examined. Dietary vitamin E supplementation led to an increase (P < 0.05) in plasma, and longissimus muscle alpha-tocopherol levels. In minced longissimus muscle stored in 80% 02:20% CO2, lipid and oxymyoglobin oxidation were lower (P < 0.05) in muscle from vitamin E-supplemented animals compared with unsupplemented animals. Dietary Se supplementation did not significantly affect muscle Se levels, glutathione peroxidase activity, or susceptibility to lipid and oxymyoglobin oxidation in the presence or absence of vitamin E. Covariance analysis indicated that, in addition to muscle alpha-tocopherol, differences in muscle glutathione peroxidase activity, and pH could account for variation in the susceptibility of muscle to lipid and oxymyoglobin oxidation.

Characterization of the Antioxidant Status of the Heterozygous Manganese Superoxide Dismutase Knockout Mouse

The antioxidant status of several tissues (liver, kidney, lung, brain, heart, muscle, stomach, and spleen) from heterozygous manganese superoxide dismutase (MnSOD) mutant mice (Sod2−/+) was characterized. The activity of MnSOD was decreased (30 to 80%) in all tissues examined. The levels of mRNA coding for the major antioxidant enzymes (CuZnSOD, catalase, and glutathione peroxidase) were not significantly altered in liver, kidney, heart, lung, or brain in theSod2−/+mice. The activities of the enzymes were not altered in any of these tissues, with the exception of a decrease in glutathione peroxidase activity in muscle in theSod2−/+mice compared to theSod2+/+mice. Thus, there was no up-regulation of the activities of the major antioxidant enzymes to compensate for the decrease in MnSOD activity. Reduced glutathione levels were 30 to 50% lower in the lung, brain, and muscle of theSod2−/+mice compared to the wild-typeSod2+/+mice. In addition, the ratio of GSH/GSSG was decreased approximately 50% inSod2−/+muscle, indicating that the decrease in MnSOD activity in theSod2−/+mice results in some degree of oxidative stress in this tissue.

An Investigation into the Effect of Sulfonylurea Glyburide on Glutathione Peroxidase Activity in Streptozotocin-Induced Diabetic Rat Muscle Tissue

1. Four weeks of glyburide (glibenclamide) treatment (5 mg/kg, orally) was administered in type II diabetic rats and the effect of such treatment was determined on muscle glutathione peroxidase (GPx) activity. 2. GPx activity was measured by a spectrophotometric method in which its activity was coupled to the oxidation of NADPH by glutathione reductase. 3. No statistically significant difference was found in muscle GPx activity between diabetic rats and controls. 4. There was a significant difference in GPx activity between glyburide-treated diabetic and nontreated diabetic groups and between glyburide-treated control and control groups. 5. The results of this study demonstrated that diabetes did not significantly alter skeletal muscle GPx activity in diabetic rats. However, glyburide may be an effective antioxidant agent in addition to its expected insulin-like effects.

Metabolism of Selenite and Selenomethionine in the Rhesus Monkey

Female rhesus monkeys were fed a commercial monkey diet and given selenium (Se) as either selenite or selenomethionine (SeMet) in the drinking water for 11 mo. Muscle and liver biopsies were taken initially and at the end of the experiment for determination of Se levels and glutathione peroxidase (GPX) activity. Blood was collected at monthly to bimonthly intervals, and the plasma and erythrocytes were subjected to gel filtration to determine the distribution of Se among proteins of various molecular weights. At the end of the experiment, there was significantly more Se in liver, muscle and hair from the monkeys given SeMet than in tissues from those given selenite, but there were no differences in liver or muscle GPX activity between the two treatment groups. The erythrocyte and plasma Se levels were significantly higher in the monkeys given SeMet than in those receiving selenite, but there were no differences in the GPX levels between these groups. About 68% of erythrocyte Se was associated with GPX in monkeys given selenite whereas only 34% was associated with GPX in those administered SeMet. The correlation coefficient for blood Se level and erythrocyte GPX activity was 0.92 in monkeys given selenite but only 0.37 in those given SeMet. Gel filtration of plasma revealed only one Se peak for plasma from the monkeys given selenite but at least two major Se peaks for plasma from monkeys receiving SeMet. The possible implications of these results for humans are discussed, including the reasons for poor correlations of GPX activity and blood Se levels.

Selenium metabolism and supplementation in patients with muscular dystrophy

We studied selenium metabolism in patients with Duchenne muscular dystrophy and in contrast to previous reports found no significant abnormalities in these patients. Supplementation of muscular dystrophy patients and control subjects with sodium selenite (1 mg selenium/day) induced a variable rise in the activity of the selenium-dependent enzyme glutathione peroxidase in plasma and red cells, but no significant change in muscle glutathione peroxidase activities. There was no effect of selenium supplementation on disease activity in the patients with muscular dystrophy. Thiobarbituric acid-reacting substances (an index of free radical-mediated lipid peroxidation) were elevated in the muscle of patients with Duchenne muscular dystrophy in contrast to patients with other forms of muscular dystrophy and control subjects. This elevation was unaffected by selenium supplementation.