engleski

Oxidative stress in mice: effects of dietary corn oil and iron

Antioxidant status represents the balance between by-products of oxidative stress and antioxidant defence system. Oxidative stress is most commonly measured indirectly via enzymatic and non-enzymatic antioxidant markers. High Fe ingestion may result in oxidative stress and deleterious reactions such as peroxidation of polyunsaturated fatty acids and decreased antioxidant enzymes activities. The mechanism by which Fe is involved in initiating or promoting oxidative damage is not entirely clear. The aim of this study was to analyze the effect of high dietary iron (Fe) on liver antioxidant status in mice fed corn oil-enriched diet. Male Balb/c mice were fed for 3 weeks standard diets enriched with 5% by weight of corn oil, with adequate Fe (FCO group), or supplemented with 1% carbonyl Fe (FCOFe group). Control group was fed standard diet. Fe, copper (Cu), and zinc (Zn) levels in liver tissue were determined by inductively coupled plasma spectrometry. Cu/Zn superoxid dismutase (CuZnSOD) and glutathione peroxidase (GPx) activities were determined spectrophotometrically in liver homogenate supernatant. Lipid peroxidation was evaluated by measuring thiobarbituric acid-reactive species (TBARS). High-Fe diet induced 2-fold increase of hepatic Fe level. However, increase of thymic Fe level has been induced solely by dietary fat. Hepatic Cu level slightly decreased in FCO diet. In spleen, high-Fe diet induced increase of Fe level was negatively correlated with Cu level. The antioxidant status was influenced by both dietary fat and Fe. Mice fed corn oil-enriched diets had higher concentration of TBARS, with a greater increase in FCOFe diet. Hepatic CuZnSOD activity was decreased in FCO diet, and Fe supplementation caused a further decrease in the enzyme activity. These results suggest that feeding with corn oil-enriched diets increases oxidative damage by decreasing antioxidant enzyme defence. The high-Fe diet additionally affects the antioxidant defence system, further increasing the tissue’ s susceptibility to lipid peroxidation. Additionally, both corn oil- and Fe-enriched diets have increased Cu requirements in mice.

corn oil; iron; copper; zinc; superoxid dismutase; glutathione peroxidase; thiobarbituric acid reactive substances

nije evidentirano