engleski

Effect of Dietary Corn Oil and Iron on Oxidative Stress in Mice Liver

Oxidative stress is caused by an imbalance between the production of reactive species and a biological system's ability to readily detoxify them. The methods for measuring oxidative stress often involve enzymatic and nonenzymatic markers. High content of dietary iron may result with increased lipid peroxidation and decreased activities of antioxidant enzymes. The mechanisam of iron involvement in initiation and promotion of oxidative damage is not entirely elucidated. The objective of this study was to investigate the effects of dietary iron and corn oil modifications designed to enhance oxidative damage in mice liver. Male Balb/c mice were divided in three groups and fed for three weeks. First group was fed standard diet enriched with 5% (w/w) of corn oil with adequate Fe (FCO group), second group was fed standard diet supplemented with 1% (w/w) of carbonyl Fe (FCOFe group). Third group was control group fed with standard diet. Fe, copper and zinc levels in liver tissue were determined by inductively coupled plasma spectrometry. Superoxide dismutase (CuZnSOD) and glutathione peroxidase (GPx) activities were determined spectrophotometricaly in liver homogenates. Lipid peroxidation was evaluated by measuring thiobarbituric acid reactive species (TBARS) per miligram of liver proteins. Fatty acid analysis was done by gas chromatography. Iron overloaded group had 2-fold higher Fe level. FCO group had decreased Cu level. The antioxidant status was influenced by both dietary fat and iron. Mice fed corn oil enriched diets had higher concentration of TBARS, with greater increase in FCOFe group. Hepatic CuZnSOD activity was decreased in FCO group and decreased furthermore after iron supplementation. These results suggest that feeding with corn oil enriched diets increases oxidative damage by lowering CuZnSOD and GPx activities. Iron supplementation further increases the tissue susceptibility to lipid peroxidation. Additionally, both corn oil and iron enriched diets increased Cu requirements in mice.

corn oil; iron; oxidative stress; liver

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