Effects of manganese and vitamin E deficiencies on antioxidant enzymes in streptozotocin-diabetic rats

Abstract Vitamin E and manganese deficiencies have been shown independently to affect the capacity to scavenge endogenously produced reactive oxygen species (ROS) in streptozotocin (STZ)-diabetic, Sprague-Dawley rats. Whether combined vitamin E and manganese deficiencies would additively affect oxidative stress was assessed in this study. Plasma and hepatic vitamin E were severely depleted in vitamin E-deficient rats, and susceptibility to lipid peroxidation in kidney, heart, liver, and pancreas tissues was increased, independent of manganese. Activities of key antioxidant enzymes, including superoxide dismutase, glutathione peroxidase, glutathione reductase, and catalase in heart, liver, kidney, and pancreas were altered by manganese and vitamin E deficiencies, although no additive effects were observed. Hemoglobin glycosylation was elevated in vitamin E-deficient, diabetic rats, an effect that further underscores the increased oxidative stress in vitamin E deficiency states.