Oxidative and biochemical responses in Brycon amazonicus anesthetized and sedated with Myrcia sylvatica (G. Mey.) DC. and Curcuma longa L. essential oils.

OBJECTIVE: To investigate the effects of rapid anesthesia and long-term sedation with the essential oils (EOs) of Myrcia sylvatica (EOMS) and Curcuma longa (EOCL) on biochemical and oxidative parameters in matrinxã. STUDY DESIGN: Prospective, randomized, laboratory experiment. ANIMALS: A total of 72 matrinxã (Brycon amazonicus) adults weighing 404.8 ± 27.9 g were divided into eight groups of nine fish. METHODS: Biochemical and oxidative effects were investigated in plasma and tissues of matrinxã subjected to rapid anesthesia (5 minutes) or long-term sedation (360 minutes, simulating the practice of transport) with EOMS (200 µL L-1 and 10 µL L-1, respectively) and EOCL (500 µL L-1 and 40 µL L-1, respectively). RESULTS: Transport simulation without sedation or anesthesia increased lipid peroxidation levels in the gills and kidney of fish in the control group. Anesthesia and sedation with EOs decreased cortisol concentrations and increased lactate concentrations compared with controls. Lipid peroxidation was lower in the brain, gills, liver and kidney of sedated and anesthetized fish, than in the control group. Anesthesia with EOs increased the activity of superoxide dismutase and glutathione-S-transferase in the brain, and catalase in the liver and gills, compared with controls. Long-term sedation with EOs increased superoxide dismutase, glutathione peroxidase and glutathione reductase activities in the brain, catalase in the liver, glutathione peroxidase and glutathione reductase in the gills and superoxide dismutase in the kidney. In general, nonprotein thiols content and total reactive antioxidant potential of tissues were higher after anesthesia and sedation with EOs compared with the control group. CONCLUSIONS AND CLINICAL RELEVANCE: The concentrations of EOMS and EOCL used were effective at preventing a stress response and excess of reactive oxygen species formation. For these reasons, these substances may be recommended for use in the transportation of fish to improve survival and animal welfare.

Effect of diets enriched with rutin on blood parameters, oxidative biomarkers and pituitary hormone expression in silver catfish (Rhamdia quelen).

The effects of adding rutin to the diet (0, 0.15 or 0.30%) of silver catfish for 21 days on blood parameters, oxidative stress biomarkers and pituitary hormones expression were investigated. Fish that received the diet containing 0.15% rutin exhibited reduced plasma cortisol levels. The levels of lipid peroxidation were lowered in the all tissues of animals receiving the diet containing rutin. Rutin increased the activity of the superoxide dismutase (SOD), catalase (CAT), nonprotein thiols (NPSH), ascorbic acid content (AA) and total reactive antioxidant potential (TRAP) in the brain; glutathione S-transferase (GST) activity and TRAP in the gills; SOD, CAT and GST activity, NPSH, AA levels and TRAP in the liver; CAT and GST activity and TRAP levels in the kidneys; and glutathione peroxidase activity, NPSH, AA levels and TRAP in the muscle. There were no changes regarding the expression of growth hormone, prolactin and somatolactin in fish fed with the diet containing rutin when compared with the control. The supplementation of rutin to the diet of fish is beneficial because it increases the antioxidant responses of tissues.

The protective effect of N-acetylcysteine on oxidative stress in the brain caused by the long-term intake of aspartame by rats.

Long-term intake of aspartame at the acceptable daily dose causes oxidative stress in rodent brain mainly due to the dysregulation of glutathione (GSH) homeostasis. N-Acetylcysteine provides the cysteine that is required for the production of GSH, being effective in treating disorders associated with oxidative stress. We investigated the effects of N-acetylcysteine treatment (150 mg kg(-1), i.p.) on oxidative stress biomarkers in rat brain after chronic aspartame administration by gavage (40 mg kg(-1)). N-Acetylcysteine led to a reduction in the thiobarbituric acid reactive substances, lipid hydroperoxides, and carbonyl protein levels, which were increased due to aspartame administration. N-Acetylcysteine also resulted in an elevation of superoxide dismutase, glutathione peroxidase, glutathione reductase activities, as well as non-protein thiols, and total reactive antioxidant potential levels, which were decreased after aspartame exposure. However, N-acetylcysteine was unable to reduce serum glucose levels, which were increased as a result of aspartame administration. Furthermore, catalase and glutathione S-transferase, whose activities were reduced due to aspartame treatment, remained decreased even after N-acetylcysteine exposure. In conclusion, N-acetylcysteine treatment may exert a protective effect against the oxidative damage in the brain, which was caused by the long-term consumption of the acceptable daily dose of aspartame by rats.

Effects of subchronic manganese chloride exposure on tambaqui (Colossoma macropomum) tissues: oxidative stress and antioxidant defenses.

This study aimed to evaluate oxidative stress parameters in juvenile tambaqui (Colossoma macropomum) exposed to 3.88 mg l(-1) Mn(2+) for 96 hours. Biomarkers of oxidative stress, such as thiobarbituric acid reactive substances (TBARS), superoxide dismutase (SOD), catalase (CAT), and glutathione-S-transferase (GST) activities, as well as content of reduced glutathione (GSH), were analyzed in gill, liver, brain, and kidney. The presence of Mn(2+) in the water corresponded to increased levels of Mn(2+) accumulation according to the following sequence: gill > kidney > brain > liver. There was a significant increase in TBARS levels (40 %) and SOD activity (80 %) in addition to a significant decrease in GSH content (41 %) in gills of fish exposed to waterborne Mn(2+). In hepatic tissue of the exposed animals, TBARS levels decreased significantly (35 %), whereas SOD (82 %) and GST activities (51 %) as well as GSH content (43 %) increased significantly. In brain of exposed juvenile fish, only significant decreases in SOD (32 %) and CAT activities (65 %) were observed. Moreover, the kidney of exposed fish showed a significant increase in TBARS levels (53 %) and a significant decrease in SOD activity (41 %) compared with the control. Thus, the changes in biomarkers of oxidative stress were different in the tissues, showing a specific toxicity of this metal to each organ.

Rutin-added diet protects silver catfish liver against oxytetracycline-induced oxidative stress and apoptosis.

It is unknown whether the flavonoid rutin can protect the silver catfish liver in response to exposure to a known stressor, such as the prophylactic usage of the antimicrobial agent oxytetracycline. Thus, the current study aimed to assess the effect of rutin incorporation into the silver catfish diet formulation on oxytetracycline-induced liver oxidative stress and apoptosis. Fish were split into four groups as follows: control, rutin (1.5 g kg diet-1), oxytetracycline (0.1 g kg diet-1) and rutin+oxytetracycline (1.5 g kg diet-1 and 0.1 g kg diet-1, respectively). After two weeks of feeding with the different diets (standard, rutin-, oxytetracycline and rutin+oxytetracycline-added diets), fish were euthanized to collect the liver. Although the rutin-added diet was unable to recover glutathione peroxidase activity, ascorbic acid and reduced glutathione (GSH) levels, which were depleted due to oxytetracycline consumption, it markedly diminished the oxidized glutathione (GSSG) content, thus decreasing the GSSG to GSH ratio, an important index of oxidative stress. It also increased glutathione reductase and markedly augmented glucose-6-phosphate dehydrogenase activities, which were declined after oxytetracycline ingestion. Furthermore, the rutin-added diet reestablished superoxide dismutase and catalase activities and reduced lipid peroxidation, nitric oxide and superoxide anion levels as well, all changes resulting from oxytetracycline consumption. Finally, it also prevented oxytetracycline-induced apoptosis through increasing heat shock protein 70 and markedly decreasing high mobility group box 1 and, consequently, reducing cleaved caspase-3 protein levels. Therefore, in conclusion, the incorporation of this flavonoid to the silver catfish diet protected the liver against oxytetracycline-induced liver oxidative stress and apoptosis.

Quercetin attenuates endocrine and metabolic responses to oxytetracycline in silver catfish (Rhamdia quelen).

This study aimed to verify whether dietary quercetin protects against the detrimental effects induced by oxytetracycline (OTC) administration in silver catfish (Rhamdia quelen). Fish were divided into different experimental groups that received OTC and/or quercetin, either during 14 or 21 days. To determine the endocrine system stress response, we have measured the brain mRNA expression levels of corticotropin-releasing hormone (crh), proopiomelanocortins (pomca and pomcb) and some of the pituitary hormones (growth hormone [gh], somatolactin [sl], and prolactin [prl]). We have also quantified the levels of cortisol as well as some metabolites (glucose, glycogen, lactate, and triglycerides) in the plasma. Moreover, the enzymatic activity of hexokinase, phosphorylase (active GPase), fructose-biphosphatase (FBP), glycerol-3-phosphate dehydrogenase, glucose-6-phosphate dehydrogenase, and glutamate dehydrogenase (GDH) and gill Na+/K+-ATPase were measured. The results demonstrated that OTC activates the silver catfish stress response by increasing the plasma cortisol and decreasing the glucose levels at 14 and 21 days. Additionally, OTC also altered the fish hepatic metabolic status as demonstrated by an increase in triglycerides levels and the enzymatic activity of both FBP and GDH after 14 days. OTC also stimulated Na+/K+-ATPase activity in the gill after 14 days and altered the hypophyseal expression of gh (at 14 and 21 days) and prl (at 14 days). The co-treatment with 1.5 g of quercetin could prevent most of the alterations caused by OTC, strongly suggesting quercetin as a beneficial compound when added to the fish diet.

Myrcia sylvatica essential oil mitigates molecular, biochemical and physiological alterations in Rhamdia quelen under different stress events associated to transport.

The effects of pre-transport handling and addition of essential oil of Myrcia sylvatica (EOMS) during transport on stress pathways activation in Rhamdia quelen were investigated. Fish (n=400, 25.2±2.9g) were captured in production ponds and transferred to 100-L tank (density 100g L-1). After 24h, 10 fish were sampled (before transport group). The remaining fish were placed in plastic bags (n=30 or 32 fish per bag, density 150g L-1) containing 5L of water (control), ethanol (315µLL-1, vehicle) or EOMS (25 or 35µLL-1), in triplicate, transported for 6h and sampled (n=10 animals per group). Indicators of stress and metabolism, as well as mRNA expression of brain hormones were evaluated. Previously, full-length cDNAs, encoding specific corticotropin-releasing hormone (crh) and proopiomelanocortins (pomca and pomcb), were cloned from whole brain of R. quelen. Crh expression increased after 24h of capture and handling, whereas cortisol and glucose plasmatics enhanced their values in the control group. Transport with EOMS reduced plasma cortisol and lactate levels, while ethanol and EOMS groups increased Na+/K+-ATPase gill activity compared to control. Gene expression of crh, pomcb, prolactin and somatolactin mRNAs were lower after transport with EOMS compared to control. EOMS was able to mitigate the stress pathways activation caused by transport, maintaining a balance in body homeostasis. Thus, EOMS is recommended as sedative in procedures as transport and the pre-transport handling requires greater attention and use of tranquilizers.

Resveratrol prevents oxidative damage and loss of sperm motility induced by long-term treatment with valproic acid in Wistar rats.

Valproic acid (VPA) is a drug widely use for the treatment of epilepsy in both children and adults. Evidence suggests that long-term use of VPA may lead to an impairment in the male reproductive function. Oxidative stress is considered to play a major role in VPA associated toxicity. In the present work, we demonstrated that the natural antioxidant compound resveratrol (RSV) can be use to prevent VPA oxidative damage. Wistar rats treated with VPA (400mgkg(-1)) by gavage for 28days showed decrease in sperm motility accompanied by increase in oxidative damage to lipids and proteins. Additionally, VPA administration leaded to depletion of reduced glutathione and decrease in total antioxidant potential in testes and epididymides of Wistar rats. The co-administration of RSV (10mgkg(-1)) efficiently prevented VPA pro-oxidant effects. In summary, RSV was shown to protect the reproductive system from the damage induced by VPA. Altogether, our data strongly suggests that RSV administration might be a valuable strategy to minimize reproductive impairment in patients requiring long-term VPA treatment.

Protective effect of vitamin E on sperm motility and oxidative stress in valproic acid treated rats.

Long-term administration of valproic acid (VPA) is known to promote reproductive impairment mediated by increase in testicular oxidative stress. Vitamin E (VitE) is a lipophilic antioxidant known to be essential for mammalian spermatogenesis. However, the capacity of this vitamin to abrogate the VPA-mediated oxidative stress has not yet been assessed. In the current study, we evaluated the protective effect of VitE on functional abnormalities related to VPA-induced oxidative stress in the male reproductive system. VPA (400 mg kg(-1)) was administered by gavage and VitE (50 mg kg(-1)) intraperitoneally to male Wistar rats for 28 days. Analysis of spermatozoa from the cauda epididymides was performed. The testes and epididymides were collected for measurement of oxidative stress biomarkers. Treatment with VPA induced a decrease in sperm motility accompanied by an increase in oxidative damage to lipids and proteins, depletion of reduced glutathione and a decrease in total reactive antioxidant potential on testes and epididymides. Co-administration of VitE restored the antioxidant potential and prevented oxidative damage on testes and epididymides, restoring sperm motility. Thus, VitE protects the reproductive system from the VPA-induced damage, suggesting that it may be a useful compound to minimize the reproductive impairment in patients requiring long-term treatment with VPA.

N-acetylcysteine protects the rat kidney against aspartame-induced oxidative stress.

Long-term intake of aspartame at the acceptable daily ingestion dose causes oxidative stress in the rat kidney through the dysregulation of glutathione homeostasis. N-acetylcysteine (NAC) provides the cystein required for the production of GSH, being effective in treating disorders associated with oxidative stress. The aim of this research was to investigate the effects of NAC on the aspartame-induced oxidative stress in the rat kidney. The animals received aspartame by gavage for six weeks (40mg/kg). From the 5th week, NAC (1mmol/kg, via intraperitoneal) was injected for two weeks. Then, they were anaesthetized for blood sample and euthanized for the kidney collection. The blood was centrifuged at 1800g for 15min and the serum was separated for creatinine measurement. The tissue was homogenized in 1.15% KCl buffer and centrifuged at 700g for 10min at 4°C. The supernatant fraction obtained was used to the measurements of oxidative stress biomarkers. The creatinine levels were enhanced in the serum of aspartame-treated rats. NAC caused a reduction in the thiobarbituric acid reactive substances, lipid hydroperoxides, carbonyl protein and hydrogen peroxide levels, which were increased in the kidney of aspartame-treated animals. Additionally, NAC caused an elevation in the glutathione peroxidase and glutathione reductase activities, total glutathione, ascorbic acid, and total reactive antioxidant potential levels, which were decreased in the kidney of aspartame-treated rats. In conclusion, NAC may be useful for the protection of the rat kidney against aspartame-induced oxidative stress.

Humic acid and moderate hypoxia alter oxidative and physiological parameters in different tissues of silver catfish (Rhamdia quelen).

Aquatic animals are naturally exposed simultaneously to environments with different concentrations of humic acid (HA) and seasonal or daily variations of dissolved oxygen (DO) levels. This study investigated the effects of simultaneous exposure to different HA and DO levels on plasma ion levels and some hematological and oxidative parameters in different tissues of silver catfish (Rhamdia quelen). The fish were exposed to 0, 2.5 or 5 mg L(-1) HA for 120 h. After this period, each group was divided into two groups: normoxia and hypoxia. Exposure to the different DO levels lasted 96 h, totaling 216 h of experimentation. At the end of the experimental period, blood sampling was performed, and the fish were euthanized prior to the excision of the gills and the brain to evaluate hematological and oxidative parameters. To verify the antioxidant capacity of HA, total phenolic compounds were measured. In general, all tissues of silver catfish exposed simultaneously to hypoxia and different HA concentrations showed a reduction in lipid peroxidation levels, as well as a modulation of the antioxidant system. These effects occurred in an HA concentration-dependent manner. Thus, HA is beneficial to silver catfish exposed to hypoxia. These beneficial effects can be attributed, most likely, to the action of the different HA constituents and functional groups, including phenolic compounds, which have antioxidant properties.

Resveratrol improves sperm motility, prevents lipid peroxidation and enhances antioxidant defences in the testes of hyperthyroid rats.

Hyperthyroidism may lead to a loss of sperm motility and an increase in oxidative stress (OS) in testes and may cause male reproductive disorders. Thus, the use of compounds with antioxidant properties may be a strategy for preventing these disorders. The effect of resveratrol (RSV) on sperm motility and on variables of the antioxidant status in the testes of rats with triiodothyronine-induced hyperthyroidism (100µg/kg) was investigated. Hyperthyroid rats presented lower sperm motility, higher levels of lipid hydroperoxides and thiobarbituric reactive substances, lower catalase and glutathione peroxidase activities and higher glutathione-S-transferase activity in their testes than control animals. RSV treatment (1mg/kg and 10mg/kg) was able to prevent these effects in the hyperthyroid rats and had no effect in the control animals. In conclusion, RSV might be a strategy for therapeutic intervention to preserve sperm motility and to prevent OS in testes, preserving testicular function in those with hyperthyroidism.

Effects of parboiled rice diet on oxidative stress parameters in kidney of rats with streptozotocin-induced diabetes.

The effect of parboiled rice (PR) and white rice (WR) diets on oxidative stress (OS) parameters was investigated in the kidneys of rats with streptozotocin-induced diabetes (40 mg kg(-1), iv). The experimental groups (n=8) were control fed with PR (CPR), control fed with WR, diabetic fed with PR, and diabetic fed with WR. After 30 days of treatment, all animals were anesthetized and exsanguinated before removal of kidneys, which were used to determine thiobarbituric acid reactive substances (TBARS), lipid hydroperoxides, carbonyl protein, superoxide dismutase, catalase, glutathione peroxidase (GPx), glutathione reductase, glutathione-S-transferase activities, and levels of glutathione (GSH). Total phenolic compounds were determined in WR and PR grains. Our data indicated that diabetes induced increase in TBARS and lipid hydroperoxides levels. Although PR has not prevented the rise in the levels of these measurements, its consumption by our animals resulted in higher GPx activity and GSH content than that of the CPR. Moreover, PR also presented concentration of total phenolic compounds 127% higher than WR grains. Thus, its consumption in this diabetic condition is suggested because this seems to confer greater protection against OS in the renal tissue of diabetic animals.

Oxidative stress parameters in juvenile brazilian flounder Paralichthys orbignyanus (Valenciennes, 1839) (Pleuronectiformes: Paralichthyidae) exposed to cold and heat shocks

The aim of this study was to determine oxidative stress parameters in the liver and gill of Brazilian flounder juveniles (307.0 ± 16.0 g and 30.0 ± 4.0 cm) submitted to different water temperature (17.1, 23.0 and 28.8ºC) for 72 h and maintained at salinity 25‰. After the acclimation of 7 days, in 23ºC, fish were transferred to 200 L tanks containing seawater (salinity 25‰) at 28.8ºC (heat shock), 17.1ºC (cold shock) or 23.0ºC (control), five replicates (five fish tank-1). The sampled collection occurred in 0 (pre-challenge), 3, 24, 48 and 72 h after temperature shock. Flounder exposed to 17.1ºC and 28.8ºC showed significantly higher TBARS levels and GST activity in the liver post-exposition (PE) in relation to the control (23ºC). CAT activity in liver present a significantly increase at 17.1ºC, in first 48 h, and subsequently decrease in 72 h PE in relation to 28.8ºC. The gills of flounder showed significantly higher TBARS levels, GST and CAT activity when submitted at 17.1 and 28.8ºC in relation to 23.0ºC. There were observed changes in lipid peroxidation levels (LPO), CAT and GST activities in the liver and gill of Brazilian flounder in response to reactive oxygen species (ROS) produced by thermal shocks.

O objetivo deste estudo foi determinar os parâmetros de estresse oxidativo no fígado e brânquias de juvenis de linguado (307,0 ± 16,0 g e 30,0 ± 4,0 cm) submetidos a diferentes temperaturas da água (17,1, 23,0 e 28,8ºC) por 72 h e mantidos na salinidade de 25‰. Após uma aclimatação de sete dias, em 23ºC, os peixes foram transferidos para tanques de 200 L contendo água do mar (salinidade 25‰) em 28,8ºC (choque quente), 17,1ºC (choque frio) ou 23,0ºC (controle), cinco repetições (cinco peixes/tanque). A coleta de amostras ocorreu em 0 (pré-exposição), 3, 24, 48 e 72 h após o choque térmico. O linguado exposto a 17,1ºC e 28,8ºC apresentaram um significante aumento dos níveis de TBARS e atividade da GST no fígado pós-exposição (PE) em relação ao controle (23ºC). A atividade da CAT no fígado apresentou um aumento significativo em 17,1ºC, nas primeiras 48 h, e subsequente diminuição em 72 h PE em relação a 28,8ºC. As brânquias do linguado apresentaram significante aumento dos níveis de TBARS e atividade da GST e CAT quando submetidos a 17,1ºC e 28,8ºC em relação a 23,0ºC. Foram observadas alterações nos níveis de peroxidação lipídica (LPO) e atividade de GST e CAT no fígado e brânquias de linguado em resposta as espécies reativas de oxigênio (ROS) produzidas pelo choque térmico.