Vitamin E effects on indexes of lipid peroxidation in muscle from DHEA-treated and exercised rats

Abstract

Sixty-four male Sprague-Dawley rats were randomly assigned to one of eight treatment groups to determine the effects of vitamin E (VitE), dehydroepiandrosterone (DHEA), and exercise on antioxidant status in plasma and skeletal muscle. Indexes of oxidative stress were determined by measuring two markers of lipid peroxidation and the activity of two free radical scavenging enzymes. One-half of the rats had their diets supplemented with 250 IU VitE/kg of diet. One-half of the rats were injected with 0.35 mol/kg body wt ip of DHEA-acetate, whereas the others were injected with vehicle. All treatments lasted 5 wk. Before being killed, one-half of each treatments group of rats was randomly assigned to run for 1 h on a motorized rodent treadmill at 21 m/min up a 12% grade. The other rats remained rested before being killed. Exercise increased thiobarbituric acid-reactive substances (TBARS) and lipid hydroperoxides in plasma and TBARS in red slow-twitch and white fast-twitch muscles. VitE reduced the amount of lipid hydroperoxides and TBARS in plasma and TBARS in all three muscle fiber types. VitE also reduced glutathione peroxidase (GPX) activity in plasma and red fast-twitch muscle. DHEA increased indexes of oxidative stress in plasma and white fast-twitch muscle. DHEA reduced GPX activity in plasma but increased GPX activity in all three muscle fiber types. These results indicate that aerobic exercise is a mild oxidative stressor with DHEA exacerbating this response and that VitE helps diminish this effect in certain muscle fiber types.

Aspectos atuais sobre estresse oxidativo, exercícios físicos e suplementação

“…However, no study has demonstrated improvement in performance after supplementation in non-deficient individuals (34)(35) . Due to α-tocoferol efficiency in reacting with peroxyl radicals, many studies have been conducted with the purpose to evaluate the effect of α-tocoferol supplementation in the LP, caused by oxidative stress induced by physical exercise.…”

“…Due to α-tocoferol efficiency in reacting with peroxyl radicals, many studies have been conducted with the purpose to evaluate the effect of α-tocoferol supplementation in the LP, caused by oxidative stress induced by physical exercise. Goldfarb et al (35) have observed smaller concentrations of lipidic hydroperoxides and thiobarbituric acid reactive substances (TBARS) in the plasma and in muscular fibers of rats submitted to intense exercise and supplemented for five weeks with α-tocoferol (250 UI α-tocoferol/kg of diet). Metin et al (36) also verified reduction in the TBARS concentration in rats supplemented with α-tocoferol (30 mg/kg/day) and training in swimming.…”

Akut Egzersi̇zi̇n Futbolcularda Anti̇oksi̇dan Si̇stem Parametreleri̇ne Etki̇si̇

“…MDA'nın egzersizin şiddet ve süresiyle orantılı olarak oksidatif strese neden olduğu ve lipid peroksidasyon reaksiyonlarını arttırdığı düşünülmektedir (31,32). Oksijen kulanımının düşük olduğu durumlarda süperoksit radikali ve onun türevleri antioksidan savunma ile zararsızlaştırılır.…”

Exercise and oxidative stress: Sources of free radicals and their impact on antioxidant systems

“…Kanter et al (28) show that daily supplementation with a vitamin mixture containing 600 mg oL-tocopherol for 6 weeks significantly decreased levels of serum MDA and expired pentane, both at rest and after 30 min of treadmill exercise at 60 and 90% VO2max. Goldfarb et al (62) report that rats supplemented with a 250 IU vitamin E/kg diet for 5 weeks have lower TBARS and lipid peroxide levels in plasma and leg muscles after one hour treadmill exercise compared to controls. Sumida et al (63) also demonstrate a protective effect with vitamin E supplementation (300 mg/day) in reducing serum MDA concentration and enzyme markers of tissue damage during exercise.…”