Effects of Dietary Vitamin E and Selenium on Antioxidative Defense Mechanisms in the Liver of Rats Treated with High Doses of Glucocorticoid

Abstract

The aim of this work was to determine the effects of dietary intake vitamin E and selenium (Se) on lipid peroxidation as thiobarbituric acid reactive substances (TBARS) and on the antioxidative defense mechanisms in the liver of rats treated with high doses of prednisolone. Two hundred fifty adult male Wistar rats were randomly divided into five groups. The rats were fed a normal diet, but groups 3, 4, and 5 received a daily supplement in their drinking water of 20 mg vitamin E, 0.3 mg Se, and a combination of vitamin E and Se, respectively, for 30 d. For 3 d subsequently, the control group (group 1) was treated with a placebo, and the remaining four groups were injected intramuscularly with 100 mg/kg body weight (BW) prednisolone. After the last administration of prednisolone, 10 rats from each group were killed at 4, 8, 12, 24, and 48 h and the activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT) enzymes and the levels of glutathione (GSH) and TBARS in their livers were measured. GSH-Px, SOD, and CAT enzyme activities and GSH levels in prednisolone-treatment group (group 2) began to decrease gradually at 4 h, falling respectively to 38%, 55%, and 40% of the control levels by 24 h, and recovering to the control levels at 48 h. In contrast, prednisolone administration caused an increase in the hepatic TBARS, reaching up to four times the levels of the control at 24 h. However, supplementation with vitamin E and Se had a preventive effect on the elevation of the hepatic TBARS and improved the diminished activities of the antioxidative enzymes and the levels of GSH. Therefore, the present study demonstrates the effectiveness of vitamin E and Se in reducing hepatic damage in glucocorticoid- treated rats and suggests that reductions in increased TBARS as a result of prednisolone may be an important factor in the action of vitamin E and Se.

Effects of additional vitamin E and selenium supply on antioxidative defence mechanisms in the kidney of rats treated with high doses of glucocorticoid

“…LPO, was enhanced by high doses of prednisolone in the kidneys of rats, as was the case in our earlier observations in the liver, 9 and that vitamin E and Se minimized these effects. It was found that high doses of GCs led to oxidative stress in the whole body, since the TBARS concentration in plasma increased.…”

“…These findings are almost identical to our earlier observations in the liver. 9 It is likely that in the kidney, vitamin E prevents the formation of LPO caused by high dose GC by scavenging free radicals.…”

“…In our previous study, we also observed that -tocopherol decreased peroxidative tissue damage by promoting the antioxidative defence systems in the liver of rats treated with a high dose of prednisolone. 9 The most important metabolic role of selenium (Na 2 SeO 3 , Se) in mammalian species is its function in the active site of selenoenzyme glutathione peroxidase (GSH-Px, E.C. 1.11.1.9).…”

Preventive Effect of Zinc Against Cadmium-induced Oxidative Stress in the Rat Testis

“…Fractions of testes (500 mg) were homogenized in buffer [Tris 10 mM, ethylenediaminetetraacetic acid (EDTA) 1 mM, PMSF 1 mM, pH=7.5; Sigma-Aldrich Chemicals, St. Louis, MO, USA)]. The homogenates were centrifugated at 600 × g for 10 min and recentrifugated at 13,000 × g for 20 min at 4 C to obtain a postnuclear homogenate and postmitochondrial supernatant fractions [19].…”

Effects of Maternal and Progeny Dietary Vitamin Regimens on the Performance of Ducklings

“…Of particular interest is the increased SOD level observed in ducklings from the maternal high-vitamin premix group. The effects of dietary vitamins on antioxidant enzyme activities remain controversial (Musalmah et al, 2002;Beytut and Aksakal, 2003).…”