Toxicity of copper intake: lipid profile, oxidative stress and susceptibility to renal dysfunction

The present study was carried out to investigate the effects of copper (Cu) intake on lipid profile, oxidative stress and tissue damage in normal and in diabetic condition. Since diabetes mellitus is a situation of high-risk susceptibility to toxic compounds, we examined potential early markers of Cu excess in diabetic animals. Male Wistar rats, at 60-days-old were divided into six groups of eight rats each. The control(C) received saline from gastric tube, the no-diabetic(Cu-10), treated with 10 mg/kg of Cu(Cu(++)-CuSO(4), gastric tube), no-diabetic with Cu-60mg/kg(Cu-60), diabetic(D), diabetic low-Cu(DCu-10) and diabetic high-Cu(DCu-60). Diabetes was induced by an ip injection of streptozotocin (60mg/kg). After 30 days of treatments, no changes we're observed in serum lactate dehydrogenase, alanine transaminase and alkaline phosphatase; indicating no adverse effects on cardiac and hepatic tissues. D-rats had glucose intolerance and dyslipidemic profile. Cholesterol and LDL-cholesterol were higher in Cu-60 and DCu-60 than in C, Cu-10 and D and DCu-10 groups respectively. Cu-60 rats had higher lipid hydroperoxide (HP) and lower superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) serum activities than C and Cu-10 rats. LH was increased and GSH-Px was decreased, while no alterations were observed in SOD and catalase in serum of DCu-60 animals. DCu-60 rats had increased urinary glucose, creatinine and albumin. In conclusion, Cu intake at high concentration induced adverse effects on lipid profile, associated with oxidative stress and diminished activities of antioxidant enzymes. Diabetic animals were more susceptible to copper toxicity. High Cu intake induced dyslipidemic profile, oxidative stress and kidney dysfunction in diabetic condition. Copper renal toxicity was associated with oxidative stress and reduction at least, one of the antioxidant enzymes. (C) 2004 Elsevier Ltd. All rights reserved

Efeito da suplementação com ácido linoléico conjugado e do treinamento em natação sobre a composição corporal e os parâmetros bioquímicos de ratos Wistar em crescimento Effect of conjugated linoleic acid supplementation and swimming training on the body composition and biochemical parameters of Wistar pups

OBJETIVO: Avaliar os efeitos da suplementação com ácido linoléico conjugado, associada ao treinamento moderado em natação, sobre a composição corporal, o consumo e a eficiência alimentar, a glicemia, o perfil lipídico e o glicogênio muscular e hepático de ratos Wistar. MÉTODOS: Ratos Wistar (30 dias) foram divididos em: sedentário, sedentário suplementado, treinado e treinado suplementado. Permaneceram em gaiolas individuais com comida e água ad libitum, temperatura de 23ºC (com variação de1ºC) e ciclo claro-escuro de 12 horas, durante 8 semanas. A sessão de natação durou 1 hora e foi realizada três vezes/semana, bem como a suplementação com ácido linoléico conjugado a 2%. Após sacrifício, o plasma, os tecidos adiposos brancos e o marrom, o músculo gastrocnêmio e o fígado foram coletados e pesados. RESULTADOS: A suplementação per se não promoveu modificação na ingestão alimentar e na massa corporal dos animais. Houve aumento na glicemia de jejum (p<0,05), nas lipoproteínas de alta densidade (p<0,05), no colesterol total (p<0,05) e redução dos triacilgliceróis. A suplementação associada ao treinamento reduziu a massa corporal (p<0,05) e aumentou o peso relativo do tecido adiposo, do fígado e a glicemia de jejum. CONCLUSÃO: A suplementação com ácido linoléico conjugado associada à prática de exercício físico parece ter influência no balanço energético, mas, por outro lado, o aumento no peso do fígado indica que a ingestão deste ácido graxo pode ter efeitos indesejáveis, aumentando as chances de desenvolvimento do fígado gorduroso. Estes achados apontam perspectivas para novos estudos envolvendo análises histológicas do fígado, expressão gênica de enzimas chaves do metabolismo lipídico e de carboidratos, associados ou não a diferentes protocolos de treinamento físico.<br>OBJECTIVE: The objective of this study was to evaluate the effects of conjugated linoleic acid supplementation associated with moderate swimming training on body composition, food efficiency and consumption, blood glucose, lipid profile, and muscle and liver glycogen of Wistar rats. METHODS: Thirty-day old Wistar rats were divided into the following groups: inactive, inactive with 2% conjugated linoleic acid supplementation, active, and active with 2% conjugated linoleic acid supplementation. They remained in individual cages with food and water ad libitum, temperature of 23±1ºC and a light and dark cycle of 12 hours for 8 weeks. The active groups swam for one hour three times per week. The animals were killed and the plasma, white and brown fat tissues, gastrocnemius muscle and liver were collected and weighted. RESULTS: Supplementation per se did not promote food intake or body weight changes in the animals. Fasting glucose (p<0.05) and high density lipoproteins (HDL, p<0.05) increased and triacylglycerols decreased. Supplementation associated with activity decreased body mass (p<0.05) and increased the relative weight of fat tissues, liver and fasting glucose. CONCLUSION: Conjugated linoleic acid supplementation associated with physical activity seems to influence energy balance. On the other hand, the increased liver weight indicates that intake of this fatty acid may have undesirable side-effects, increasing the chances of developing fatty liver. This new perspective makes way for new studies including histological analyses of the liver and gene expression of key enzymes from the lipid and carbohydrate metabolism, associated or not with different physical training protocols

Efeitos de dois tipos de treinamento de natação sobre a adiposidade e o perfil lipídico de ratos obesos exógenos Effects of two different types of swimming exercise on adiposity and lipid profile in rats with exogenous obesity

OBJETIVO: Investigar os efeitos do exercício de natação intermitente em relação ao exercício contínuo e ao sedentarismo, em ratos Wistar, após o desenvolvimento de obesidade exógena pela administração de uma dieta hiperlipídica palatável sobre: evolução do peso corporal, ingestão alimentar, adiposidade, percentual de gordura dos tecidos e perfil lipídico. MÉTODOS: Foram utilizados ratos adultos, mantidos em gaiolas individuais, com livre acesso a água e comida. O protocolo experimental incluiu: 1) desenvolvimento da obesidade exógena (3 semanas), os animais foram divididos em: P: sedentários alimentados com dieta padrão Primor® (n=8) e H: sedentários alimentados com dieta hiperlipídica (n=32); 2) tratamentos (8 semanas subseqüentes), os animais (n=24) passaram a receber dieta padrão e foram divididos em: sedentário; treinado contínuo e treinado intermitente. Treinamentos (5x semana): Contínuo (90 minutos/dia) e Intermitente (3x30min/dia). Os animais foram submetidos à eutanásia (3 e 8 semanas), sendo coletados os tecidos adiposos, o fígado e o sangue. Foram determinados a adiposidade e o percentual de gordura dos tecidos adiposos e do fígado, o ganho de peso corporal, o consumo alimentar e o perfil lipídico. RESULTADOS: A dieta hiperlipídica aumentou a adiposidade, o percentual de gordura acumulada no fígado e desenvolveu dislipidemias. A troca de dieta e os dois tipos de treinamento foram capazes de reverter o quadro de obesidade exógena. Contudo, o exercício intermitente foi mais eficiente na redução da adiposidade e de ganho de peso. CONCLUSÃO: Associados à dieta balanceada, os treinamentos aplicados neste estudo poderiam ser utilizados como estratégia no controle de peso e de dislipidemias, tanto em modelos experimentais quanto em seres humanos.<br>OBJECTIVE: The objective was to look into the effects of intermittent swimming against continuous exercise and inactivity in Wistar rats after they developed exogenous obesity though the consumption of a palatable fat-rich diet. The following was investigated: evolution of body weight, food intake, adiposity, fat percentage in tissues and lipid profile. METHODS: Adult rats were kept in individual cages with free access to food and water. The experimental protocol included: 1) development of exogenous obesity (3 weeks). The animals were divided into S - inactive animals fed the standard Primor® diet (n=8) and HF - inactive animals fed a high-fat diet (n=32); 2) Treatment (the 8 following weeks) - the animals (n=24) were given the standard diet and divided into an inactive group, a continuous training group and an intermittent training group. Training occurred 5 times per week and was either continuous (90 minutes per day) or intermittent (3 times 30 minutes per day). The animals were killed at 3 and 8 weeks and the fat tissues, the liver and the blood were collected. Adiposity, fat percentage of the fat tissues and liver, gain of body weight, food consumption and lipid profile were determined. RESULTS: The high-fat diet increased adiposity, percentage of fat in the liver, and induced dyslipidemias. Diet change and the two types of training were capable of reducing exogenous obesity. However, intermittent exercise was more efficient in reducing adiposity and preventing weight gain. CONCLUSION: When associated with a balanced diet, the trainings used in this study can be used as a strategy to control weight and dyslipidemias, both in experimental models and in human beings

Estresse oxidativo: conceito, implicações e fatores modulatórios Oxidative stress: concept, implications and modulating factors

O estresse oxidativo decorre de um desequilíbrio entre a geração de compostos oxidantes e a atuação dos sistemas de defesa antioxidante. A geração de radicais livres e/ou espécies reativas não radicais é resultante do metabolismo de oxigênio. A mitocôndria, por meio da cadeia transportadora de elétrons, é a principal fonte geradora. O sistema de defesa antioxidante tem a função de inibir e/ou reduzir os danos causados pela ação deletéria dos radicais livres e/ou espécies reativas não radicais. Esse sistema, usualmente, é dividido em enzimático (superóxido dismutase, catalase e glutationa peroxidase) e não-enzimático. No último caso, é constituído por grande variedade de substâncias antioxidantes, que podem ter origem endógena ou dietética. Objetivou-se revisar os principais mecanismos de geração de radicais livres, bem como a ação dos agentes mais relevantes do sistema de defesa antioxidante, ressaltando suas implicações sobre os marcadores do estresse oxidativo. Também serão abordados os principais fatores exógenos moduladores do estresse oxidativo.<br>There is evidence that oxidative stress, defined as a persistent imbalance between the production of highly oxidative compounds and antioxidant defenses, leads to tissue damage. Oxygen metabolism generates free radicals and/or non-radical reactive oxygen species. The mitochondria, through the electron transport chain, are the main generator of these species. The antioxidant defense system has the function of inhibiting and/or reducing the damage caused by the deleterious free radicals and/or non-radical reactive oxygen species. This system is divided into enzymatic (superoxide dismutase, catalase and glutathione peroxidase), and nonenzymatic. The nonenzymatic system consists of a variety of antioxidant substances, which may be endogenous or dietary. This study proposed to review the main mechanisms of reactive oxygen species generation and the role of the most relevant agents of the antioxidant defense system on the biomarkers of oxidative stress. The main exogenous factors that modulate oxidative stress will also be discussed