The aim of the study was to investigate the effects of zinc deficiency and supplementation on lipid peroxidation and glutathione levels in blood and in some tissues of rats performing swimming exercise. Forty adult male Sprague-Dawley rats were divided into four groups: group 1, zinc-deficient consisted of swimming rats; group 2 consisted of zinc-supplemented swimming rats; groups 3 and 4 were the swimming and nonswimming controls, respectively. The levels of malondialdehyde and glutathione were measured after 4 wk of zinc-deficient or zinc-supplemented diet and 30 min of swimming exercise daily. The erythrocyte glutathione levels of groups 2 and 4 were significantly higher than those of groups 1 and 3 (p<0.01). The plasma malondialdehyde level of group 1 was significantly higher than all other groups. The glutathione levels in liver, kidney, striated muscle, and testes of group 2 were higher than in the other groups (p<0.01) and higher in kidney and striated muscle of group 3 than in groups 1 and 4 (p<0.01). The tissue malondialdehyde levels of striated muscle, liver, kidney, and testes of group 1 were significantly higher than for all other groups (p<0.01). Our findings suggest that both swimming exercise and zinc deficiency result in an increase of lipid peroxidation in tissues and that zinc supplementation prevents these alterations by the activation of the antioxidant system.

Extremely low-frequency (0-300 Hz) electromagnetic fields (EMFs) generated by power lines, wiring and home appliances are ubiquitous in our environment. All populations are now exposed to EMF, and exposure to EMF may pose health risks. Some of the adverse health effects of EMF exposure are lipid peroxidation and cell damage in various tissues. This study has investigated the effects of EMF exposure and zinc administration on lipid peroxidation in the rat brain. Twenty-four male Sprague-Dawley rats were randomly allocated to three groups; they were maintained untreated for 6 months (control, n = 8), exposed to low-frequency (50 Hz) EMF for 5 minutes every other day for 6 months (n = 8), or exposed to EMF and received zinc sulfate daily (3 mg/kg/day) intraperitoneally (n = 8). We measured plasma levels of zinc and thiobarbituric acid reactive substances (TBARS), and levels of reduced glutathione (GSH) in erythrocytes. TBARS and GSH levels were also determined in the brain tissues. TBARS levels in the plasma and brain tissues were higher in EMF-exposed rats with or without zinc supplementation, than those in controls ( p < 0.001). In addition, TBARS levels were significantly lower in the zinc-supplemented rats than those in the EMF-exposed rats ( p < 0.001). GSH levels were significantly decreased in the brain and erythrocytes of the EMF-exposed rats ( p < 0.01), and were highest in the zinc-supplemented rats ( p < 0.001). Plasma zinc was significantly lower in the EMF-exposed rats than those in controls ( p < 0.001), while it was highest in the zinc-supplemented rats ( p < 0.001). The present study suggests that long-term exposure to low-frequency EMF increases lipid peroxidation in the brain, which may be ameliorated by zinc supplementation. electromagnetic field; lipid peroxidation; zinc; brain

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The aim of this study was to investigate the extent of lipid peroxidation when zinc is administered to rats periodically exposed to a 50-Hz electromagnetic field for 5 min at a time over a period of 6 mo. Twenty-four Sprague-Dawley adult male rats were subdivided in groups of eight animals each. Group 1 served as untreated controls, group 2 was exposed to an electromagnetic field but received no additional treatment, and group 3 was exposed to electromagnetic radiation and treated with 3-mg/kg daily intraperitoneal injections of zinc sulfate. The erythrocyte glutathione activity (GSH) and the plasma, testicle, and kidney tissue levels of zinc (Zn) and of malondialdehyde (MDA) were measured in all of the animals. The plasma and testicle MDA levels in group 2 were higher than those in groups 1 and 3, with group 3 values significantly higher than those in group 1 (p<0.001). The kidney MDA levels in group 2 were higher than in groups 1 and 3 (p<0.001). The erythrocyte GSH level was lower in group 2 than in groups 1 and 3, with group 1 significantly lower than group 3 (p<0.001). In testicle and kidney tissues, the GSH levels in group 1 were lower than for groups 2 and 3, with group 2 significantly lower than group 3 (p<0.001) The plasma zinc levels were highest in group 3, followed by group 1 and group 2, which showed the lowest value (p<0.001). These results indicate that testicle and kidney tissue damage caused by periodic exposure to an electromagnetic field are ameliorated or prevented by zinc supplementation.