Effect of dietary vitamin E on antioxidant status and antioxidant enzyme activities in Sprague-Dawley rats

The effect of dietary vitamin E an plasma, red blood cells (RBC), hepatic a ntioxidant status, and antioxidant enzyme activities was investigated. Thre e groups of six Sprague-Dawley rats were fed 0, 100, or 1,500 ppm vitamin E for eight weeks. Plasma alpha-tocopherol level was increased significantly by increasing dietary vitamin E (p < 0.05). Plasma lipid peroxidation (thi obarbituric acid-reactive substances) stimulation by I mM t-butyl hydropero xide was correlated with dietary vitamin E level and was significantly grea ter in rats fed no vitamin E than in rats fed 100 or 1,500 ppm vitamin E (p < 005). RBC reduced glutathione (GSH) level was positively correlated with dietary vitamin E and was significantly greater in rats fed 1,500 ppm vita min E than in rats fed 0 or 100 ppm vitamin E (p < 0.05). RBC oxidized glut athione was negatively correlated with dietary vitamin E. GSH redox status was expressed as the GSH-to-total GSH ratio; the ratio was also positively correlated with dietary vitamin E and was significantly greater in rats fed 1,500 ppm vitamin E than in rats fed no vitamin E (p < 005). For antioxida nt enzymes, superoxide dismutase activity in hepatic cytosolic fraction was significantly greater in rats fed 1,500 ppm vitamin E than in rats fed 100 ppm vitamin E. Hepatic GSH reductase activity was significantly greater in rats fed 100 ppm vitamin E than in rats fed no vitamin E (p < 0.05). Dieta ry vitamin E had no effect on plasma vitamin C and protein thiol levels. in the systems studied, results indicated that dietary vitamin E selectively influences plasma vitamin E level, RBC GSH status and hepatic cytosolic sup eroxide dismutase and GSH reductase activities.