The use of the oxidative stress responses as biomarkers in Nile tilapia (Oreochromis niloticus) exposed to in vivo cadmium contamination

Water contaminants have a high potential risk for the health of populations. Protection from toxic effects of environmental water pollutants primarily involves considering the mechanism of low level toxicity and likely biological effects in organisms who live in these polluted waters. The biomarkers assessment of oxidative stress and metabolic alterations to cadmium exposure were evaluated in Nile tilapia, Oreochromis niloticus. The fish were exposed to 0.35, 0.75, 1.5, and 3.0 mg/l concentrations of Cd2+ (CdCl2) in water for 60 days. Fish that survived cadmium exposure showed a metabolic shift and a compensatory development for maintenance of the body weight gain. We observed a decreased glycogen content and decreased glucose uptake in white muscle. Lactate dehydrogenase (LDH) and creatine phosphokinase (CK) activities were also decreased, indicating that the glycolytic capacity was decreased in this tissue. No alterations were observed in total protein content in white muscle due to cadmium exposure suggesting a metabolic shift of carbohydrate metabolism to maintenance of the muscle protein reserve. There was an increase in glucose uptake, CK increased activity, and a clear increase of LDH activity in red muscle of fish with cadmium exposure. Since no alterations were observed in lipoperoxide concentration, while antioxidant enzymes glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) were changed in the liver and the red and white muscle of fish with cadmium exposure, we can conclude that oxygen free radicals are produced as a mediator of cadmium toxicity. Resistance development is related with increased activities of antioxidant enzymes, which were important in the protection against cadmium damage, inhibiting lipoperoxide formation. (C) 2002 Elsevier B.V. Ltd. All rights reserved.

The effect of alpha-tocopherol on the oxidative cleavage of beta-carotene

Two cleavage pathways of beta-carotene have been proposed, one by central cleavage and the other by random (excentric) cleavage. The central cleavage pathway involves the metabolism of beta-carotene at the central double bond (15, 15') to produce retinal by beta-carotene 15, 15'-dioxygenase (E.C.888990988). The random cleavage of beta-carotene produces beta-apo-carotenoids, but the mechanism is not clear. To understand the various mechanisms of beta-carotene cleavage, beta-carotene was incubated with the intestinal postmitochondrial fractions of 10-week-old male rats for 1 h and cleavage products of beta-carotene were analyzed using reverse-phase, high-performance liquid chromatography (HPLC). We also studied the effects of alpha-tocopherol and NAD(+)/NADH on beta-carotene cleavage. In addition to beta-carotene, we used retinal and beta-apo-14'-carotenoic acid as substrates in these incubations. Beta-apo-14'-carotenoic acid is the two-carbon longer homologue of retinoic acid. In the presence of alpha-tocopherol, beta-carotene was converted exclusively to retinal, whereas in the absence of alpha-tocopherol, both retinal and beta-apo-carotenoids were formed. Retinoic acid was produced from both retinal and beta-apo-14'-carotenoic acid incubations only in the presence of NAD(+). Our data suggest that in the presence of an antioxidant such as alpha-tocopherol, beta-carotene is converted exclusively to retinal by central cleavage. In the absence of an antioxidant, beta-carotene is cleaved randomly by enzyme-related radicals to produce beta-apo-carotenoids, and these beta-apo-carotenoids can be oxidized further to retinoic acid via retinal. (C) 2000 Elsevier B.V.

Calorimetry, Morphometry, Oxidative Stress, and Cardiac Metabolic Response to Growth Hormone Treatment in Obese and Aged Rats

This study investigated the effects of growth hormone therapy on energy expenditure, lipid profile, oxidative stress and cardiac energy metabolism in aging and obesity conditions. Life expectancy is increasing in world population and with it, the incidence of public health problems such as obesity and cardiac alterations. Because growth hormone (GH) concentration is referred to be decreased in aging conditions, a question must be addressed: what is the effect of GH on aging related adverse changes? To investigate the effects of GH on cardiac energy metabolism and its association with calorimetric parameters, lipid profile and oxidative stress in aged and obese rats, initially 32 male Wistar rats were divided into 2 groups (n = 16), C: given standard-chow and water; H: given hypercaloric-chow and receiving 30 % sucrose in its drinking water. After 45 days, both C and H groups were divided into 2 subgroups (n = 8), C + PL: standard-chow, water, and receiving saline subcutaneously; C + GH: standard-chow, water, and receiving 2 mg/kg/day rhGH subcutaneously; H + PL: hypercaloric-chow, 30 % sucrose, receiving saline subcutaneously; H + GH: hypercaloric-chow, 30 % sucrose, receiving rhGH subcutaneously. After 30 days, C + GH and H + PL rats had higher body mass index, Lee-index, body fat content, percent-adiposity, serum triacylglycerol, cardiac lipid-hydroperoxide, and triacylglycerol than C + PL. Energy-expenditure (RMR)/body weight, oxygen consumption and fat-oxidation were higher in H + GH than in H + PL. LDL-cholesterol was highest in H + GH rats, whereas cardiac pyruvate-dehydrogenase and phosphofrutokinase were higher in H + GH and H + PL rats than in C + PL. In conclusion, the present study brought new insights on aging and obesity, demonstrating for the first time that GH therapy was harmful in aged and obesity conditions, impairing calorimetric parameters and lipid profile. GH was disadvantageous in control old rats, having undesirable effects on triacylglycerol accumulation and cardiac oxidative stress.

Dietary restriction and fibre supplementation: Oxidative stress and metabolic shifting for cardiac health

Dietary modification ought to be the first line of strategy in prevention of the development of cardiac disease. The purpose of this study was to investigate whether dietary restriction, dietary-fibre-enriched diet, and their interactions might affect antioxidant capacity and oxidative stress in cardiac tissue. Male Wistar rats (180-200 g; n = 10) were divided into four groups: control ad libitum diet (C), 50% restricted diet (DR), fed with fibre-enriched diet (F), and 50% restricted fibre-enriched diet (DR-F). After 35 days of the treatments, F, DR, and DR-F rats showed low cholesterol, LDL-cholesterol, and triacylglycerol, and high HDL-cholesterol in serum. The DR, DR-F, and F groups had decreased myocardial lipoperoxide and lipid hydroperoxide. The DR-F and F treatments increased superoxide dismutase and glutatione peroxidase (GSH-Px). The DR treatment increased GSH-Px and catalase activities. Dietary fibre beneficial effects were related to metabolic alterations. The F and DR-F groups showed high cardiac glycogen and low lactate dehydrogenase/citrate synthase ratios, indicating diminished anaerobic and elevated aerobic myocardial metabolism in these animals. There was no synergistic effect between dietary restriction and dietary fibre addition, since no differences were observed in markers of oxidative stress in the F and DR-F groups. Dietary fibre supplementation, rather than energy intake and dietary restriction, appears to be the main process retarding oxidative stress in cardiac tissue.

Evaluation of a protein deficient diet in rats through blood oxidative stress biomarkers

Protein malnutrition leads to functional impairment in several organs, which is not fully restored with nutritional recovery. Little is known about the role of oxidative stress in the genesis of these alterations. This study was designed to assess the sensitivity of blood oxidative stress biomarkers to a dietary protein restriction. Male Wistar rats were divided into two groups, according to the diet fed from weaning (21 days) to 60 day old: normal protein (17% protein) and low protein (6% protein). Serum protein, albumin, free fatty acid and liver glycogen and lipids were evaluated to assess the nutritional status. Blood glutathione reductase (GR) and catalase (CAT) activities, plasma total sulfhydryl groups concentration (TSG) as well as plasma thiobarbituric acid reactive substances (TBARs) and reactive carbonyl derivatives (RCD) were measured as biomarkers of the antioxidant system and oxidative damage, respectively. The glucose metabolism in soleus muscle was also evaluated as an index of stress severity imposed to muscular mass by protein malnutrition. No difference was observed in muscle glucose metabolism or plasma RCD concentration between both groups. However, our results showed that the low protein group had higher plasma TBARs (62%) concentration and lower TSG (44%) concentration than control group, indicating increased reactive oxygen species production in low protein group. The enhancement of erythrocyte GR (29%) and CAT (28%) activities in this group also suggest an adaptation to the stress generated by the protein deficiency. Taken together, the results presented here show that the biomarkers used were able to reflect the oxidative stress level induced by this specific protein deficient diet.

Toxicity of hypercaloric diet and monosodium glutamate: oxidative stress and metabolic shifting in hepatic tissue.

The present study examines the effects of a hypercaloric diet on hepatic glucose metabolism of young rats, with and without monosodium glutamate (MSG) administration, and the association of these treatments with evaluating markers of oxidative stress. Male weaned Wistar rats (21 days old) from mothers fed with a hypercaloric diet or a normal diet, were divided into four groups (n=6): control (C) fed with control diet; (MSG) treated with MSG (4 mg/g) and control diet; (HD) fed with hypercaloric diet and (MSG-HD) treated with MSG and HD. Rats were sacrificed after the oral glucose tolerance test (OGTT), at 45 days of treatments. Serum was used for insulin determination. Glycogen, hexokinase(HK), glucose-6-phosphatase(G6PH), lipid hydroperoxide, superoxide dismutase(SOD) and glutathione peroxidase(GSH-Px) were determined in liver. HD rats showed hypoglycemia, hyperinsulinemia, and high hepatic glycogen, HK and decreased G6PH. MSG and MSG-HD had hyperinsulinemia, hyperglycemia, decreased HK and increased G6PH in hepatic tissue. These animals had impaired OGTT. HD, MSG and MSG-HD groups had increased lipid hydroperoxide and decreased SOD in hepatic tissue. Hypercaloric diet and monosodium glutamate administration induced alterations in metabolic rate of glucose utilization and decreased antioxidant defenses. Therefore, the hepatic glucose metabolic shifting induced by HD intake and MSG administration were associated with oxidative stress in hepatic tissue.

Enzymatic and oxidative metabolites of lycopene.

Using the post-mitochondrial fraction of rat intestinal mucosa, we have investigated lycopene metabolism. The incubation media was composed of NAD+, KCI, and DTT with or without added lipoxygenase. The addition of lipoxygenase into the incubation significantly increased the production of lycopene metabolites. The enzymatic incubation products of 2H10 lycopene were separated using high-performance liquid chromatography and analyzed by UV/Vis spectrophotometer and atmospheric pressure chemical ionization-mass spectroscopy. We have identified two types of products: cleavage products and oxidation products. The cleavage products are likely: (1) 3-keto-apo-13-lycopenone (C18H24O2 or 6,10,14-trimethyl-12-one-3,5,7,9,13-pentadecapentaen-2-one) with lambdamax = 365 nm and m/z =272 and (2) 3,4-dehydro-5,6-dihydro-15-apo-lycopenal (C20H28O or 3,7,11,15-tetramethyl-2,4,6,8,12,14-hexadecahexaen-l-al) with lambdamax= 380 nm and m/z = 284. The oxidative metabolites are likely: (3) 2-ene-5,8-lycopenal-furanoxide (C37H50O) with lambdamax = 415 nm, 435 nm, and 470 nm, and m/z = 510; (4) lycopene-5, 6, 5', 6'-diepoxide (C40H56O2) with lambdamax = 415 nm, 440 nm, and 470 nm, and m/z =568; (5) lycopene-5,8-furanoxide isomer (I) (C40H56O2) with lambdamax = 410 nm, 440 nm, and 470 nm, and m/z = 552; (6) lycopene-5,8-epoxide isomer (II) (C40H56O) with lambdamax = 410, 440, 470 nm, and m/z = 552; and (7) 3-keto-lycopene-5',8'-furanoxide (C40H54O2) with lambdamax = 400 nm, 420 nm, and 450 nm, and m/z = 566. These results demonstrate that both central and excentric cleavage of lycopene occurs in the rat intestinal mucosa in the presence of soy lipoxygenase.

Monosodium glutamate in standard and high-fiber diets: Metabolic syndrome and oxidative stress in rats

Objective: This study determined the effects of adding monosodium glutamate (MSG) to a standard diet and a fiber-enriched diet on glucose metabolism, lipid profile, and oxidative stress in rats. Methods: Male Wistar rats (65 ± 5 g, n = 8) were fed a standard diet (control), a standard diet supplemented with 100 g of MSG per kilogram of rat body weight, a diet rich in fiber, or a diet rich in fiber supplemented with 100 g of MSG per kilogram of body weight. After 45 d of treatment, sera were analyzed for concentrations of insulin, leptin, glucose, triacylglycerol, lipid hydroperoxide, and total antioxidant substances. A homeostasis model assessment index was estimated to characterize insulin resistance. Results: Voluntary food intake was higher and feed efficiency was lower in animals fed the standard diet supplemented with MSG than in those fed the control, fiber-enriched, or fiber- and MSG-enriched diet. The MSG group had metabolic dysfunction characterized by increased levels of glucose, triacylglycerol, insulin, leptin, and homeostasis model assessment index. The adverse effects of MSG were related to an imbalance between the oxidant and antioxidant systems. The MSG group had increased levels of lipid hydroperoxide and decreased levels of total antioxidant substances. Levels of triacylglycerol and lipid hydroperoxide were decreased in rats fed the fiber-enriched and fiber- and MSG-enriched diets, whereas levels of total antioxidant substances were increased in these animals. Conclusions: MSG added to a standard diet increased food intake. Overfeeding induced metabolic disorders associated with oxidative stress in the absence of obesity. The fiber-enriched diet prevented changes in glucose, insulin, leptin, and triacylglycerol levels that were seen in the MSG group. Because the deleterious effects of MSG, i.e., induced overfeeding, were not seen in the animals fed the fiber-enriched diets, it can be concluded that fiber supplementation is beneficial by discouraging overfeeding and improving oxidative stress that is induced by an MSG diet. © 2005 Elsevier Inc. All rights reserved.

Combined effects of age and diet-induced obesity on biochemical parameters and cardiac energy metabolism in rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Energy Metabolism in Cardiac Remodeling and Heart Failure

Fatty acids are the main substrates used by mitochondria to provide myocardial energy under normal conditions. During heart remodeling, however, the fuel preference switches to glucose. In the earlier stages of cardiac remodeling, changes in energy metabolism are considered crucial to protect the heart from irreversible damage. Furthermore, low fatty acid oxidation and the stimulus for glycolytic pathway lead to lipotoxicity, acidosis, and low adenosine triphosphate production. While myocardial function is directly associated with energy metabolism, the metabolic pathways could be potential targets for therapy in heart failure. © 2013 by Lippincott Williams & Wilkins.

Infrared LED irradiation photobiomodulation of oxidative stress in human dental pulp cells

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Exercise and oxidative stress: p,otential effects of antioxidant dietary strategies in sports

Free radicals are produced during aerobic cellular metabolism and have key roles as regulatory mediators in signaling processes. Oxidative stress reflects an imbalance between production of reactive oxygen species and an adequate antioxidant defense. This adverse condition may lead to cellular and tissue damage of components, and is involved in different physiopathological states, including aging, exercise, inflammatory, cardiovascular and neurodegenerative diseases, and cancer. In particular, the relationship between exercise and oxidative stress is extremely complex, depending on the mode, intensity, and duration of exercise. Regular moderate training appears beneficial for oxidative stress and health. Conversely, acute exercise leads to increased oxidative stress, although this same stimulus is necessary to allow an up-regulation in endogenous antioxidant defenses (hormesis). Supporting endogenous defenses with additional oral antioxidant supplementation may represent a suitable noninvasive tool for preventing or reducing oxidative stress during training. However, excess of exogenous antioxidants may have detrimental effects on health and performance. Whole foods, rather than capsules, contain antioxidants in natural ratios and proportions, which may act in synergy to optimize the antioxidant effect. Thus, an adequate intake of vitamins and minerals through a varied and balanced diet remains the best approach to maintain an optimal antioxidant status. Antioxidant supplementation may be warranted in particular conditions, when athletes are exposed to high oxidative stress or fail to meet dietary antioxidant requirements. Aim of this review is to discuss the evidence on the relationship between exercise and oxidative stress, and the potential effects of dietary strategies in athletes. The differences between diet and exogenous supplementation as well as available tools to estimate effectiveness of antioxidant intake are also reported. Finally, we advocate the need to adopt an individualized diet for each athlete performing a specific sport or in a specific period of training, clinically supervised with inclusion of blood analysis and physiological tests, in a comprehensive nutritional assessment. (C) 2015 Elsevier Inc. All rights reserved.

The immune system is limited by oxidative stress: dietary selenium promotes optimal antioxidative status and greatest immune defense in pacu Piaractus mesopotamicus

Reactive oxygen species (ROS) are reactive molecules containing oxygen, that form as byproducts of aerobic metabolism, including immune system processes. Too much ROS may cause oxidative stress. In this study, we examined whether it can also limit the production of immune system compounds. To assess the relationship between antioxidant status and immunity we evaluated the effect of dietary supplementation with organic selenium, given at various levels for 10 days, on the antioxidant and immune system of the pacu fish (Piaractus mesopotamicus). Fish fed a diet containing 0.6 mg Se-yeast kg(-1) showed significant improvement in antioxidant status, as well as in hematological and immunological profiles. Specifically, they had the highest counts for catalase (CAT), glutathione peroxidase (GPx), glutathione S-transferase (GST), red blood cells, and thrombocytes; the highest leukocyte count (particularly for monocytes); and the highest serum lysozyme activity. There was also a positive correlation between GPx and lysozyme in this group of fish. These findings indicate that short-term supplementation with 0.6 mg Se-yeast kg(-1) reestablished the antioxidative status, allowing the production of innate components which can boost immunity without the risk of oxidative stress. This study shows a relationship between oxidative stress and immunity, and, from a practical perspective, shows that improving immunity and health in pacu through the administration of selenium could improve their growth performance.

PHYSIOLOGICAL CHANGES IN SEEDS AND ANTIOXIDANT METABOLISM OF LETTUCE SEEDLING EXPOSED TO THE ACTION OF Zantedeschia aethiopica Spreng. LEAF EXTRACT

This work aimed to evaluate the influence of different concentrations of Zantedeschia aethiopica Spreng. extract on the physiological performance of the seed and on the response of the antioxidant metabolism of lettuce seedlings. The treatments consisted of leaves extracts from Z. aethiopica at concentrations of 0, 6, 12, 25 and 50%. Germination, first germination count, germination speed and index, length of shoot and radicle, seedling total dry mass, chlorophyll content, activity of superoxide dismutase, catalase and ascorbarte peroxidase enzymes, lipid peroxidation, hydrogen peroxide quantification and seedling emergence, length of organs, and total dry mass of seedlings were evaluated. The percentage of germination, the length of the shoot and radicle of seedlings and the total dry mass of seedlings grown in the greenhouse were reduced as the concentration of the extract increased. There were increases of electrical conductivity, of superoxide dismutase, catalase and ascorbate peroxidadase enzymes and the amount of hydrogen peroxide and lipid peroxidation in seedlings with increasing extract concentration. The extract reduced the physiological quality of lettuce seeds and induced an increased production of hydrogen peroxide in seedlings, which increased the activity of antioxidant enzymes that were not effective in tissue detoxification, resulting in cellular damage and increased numbers of abnormal seedlings.

Experimental hyperprolinemia induces mild oxidative stress, metabolic changes, and tissue adaptation in rat liver

The present study investigated the effects of chronic hyperprolinemia on oxidative and metabolic status in liver and serum of rats. Wistar rats received daily subcutaneous injections of proline from their 6th to 28th day of life. Twelve hours after the last injection the rats were sacrificed and liver and serum were collected. Results showed that hyperprolinemia induced a significant reduction in total antioxidant potential and thiobarbituric acid-reactive substances. The activities of the antioxidant enzymes catalase and superoxide dismutase were significantly increased after chronic proline administration, while glutathione (GSH) peroxidase activity, dichlorofluorescin oxidation, GSH, sulfhydryl, and carbonyl content remained unaltered. Histological analyses of the liver revealed that proline treatment induced changes of the hepatic microarchitecture and increased the number of inflammatory cells and the glycogen content. Biochemical determination also demonstrated an increase in glycogen concentration, as well as a higher synthesis of glycogen in liver of hyperprolinemic rats. Regarding to hepatic metabolism, it was observed an increase on glucose oxidation and a decrease on lipid synthesis from glucose. However, hepatic lipid content and serum glucose levels were not changed. Proline administration did not alter the aminotransferases activities and serum markers of hepatic injury. Our findings suggest that hyperprolinemia alters the liver homeostasis possibly by induction of a mild degree of oxidative stress and metabolic changes. The hepatic alterations caused by proline probably do not implicate in substantial hepatic tissue damage, but rather demonstrate a process of adaptation of this tissue to oxidative stress. However, the biological significance of these findings requires additional investigation. J. Cell. Biochem. 113: 174183, 2012. (C) 2011 Wiley Periodicals, Inc.