Hyperglycemia-induced oxidative stress in diabetic conditions promotes alterations of function and other properties of the erythrocyte membrane. In this study, we examined the effects of palm vitamin E (200 mg/kg) on oxidative stress and the physical and morphological characteristics of erythrocyte membranes in streptozotocin-induced diabetic rats. Forty male rats were randomly divided into 4 groups as follows: Group 1, control group; Group 2, normal plus palm vitamin E treatment; Group 3, untreated diabetic group; and Group 4, diabetic plus palm vitamin E treatment. After 4 weeks of treatments, we determined complete blood count, erythrocyte osmotic fragility, erythrocyte morphology, levels of erythrocyte malondialdehyde and protein carbonyl, levels of erythrocyte glutathione and oxidized glutathione, and total plasma antioxidant capacity. The results of osmotic fragility were significantly higher in the diabetic group compared to the control and diabetic with palm vitamin E. There were significant morphological changes in the erythrocytes of the diabetic group compared to the control group. We also found a significant decrease in the hemoglobin concentration, hematocrit percentage, and erythrocyte distribution width in the diabetic group. Erythrocyte malondialdehyde and protein carbonyl levels were significantly higher in the diabetic group compared to the control group. Decreased levels of reduced glutathione and increased level of oxidized glutathione were observed in the diabetic group compared to the control and diabetic with palm vitamin E groups. Plasma total antioxidant capacity was significantly lower in the diabetic group than in the control group, whereas plasma total antioxidants in the diabetic with palm vitamin E group were significantly increased compared to the untreated diabetic group. In conclusion, 4 weeks of daily supplementation with 200 mg/kg palm vitamin E could reduce the levels of oxidative stress markers by inhibiting lipid peroxidation and protein oxidation in streptozotocin-induced diabetic rats.
Key words: Diabetes mellitus; Erythrocyte membrane; Lipid peroxidation; Oxidative stress; Palm vitamin E
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