Effect of Vitamin E Supplementation on Oxidative Stress in a Rat Model of Diet-induced Obesity

Objective: To evaluate the effect of vitamin E on the level of oxidative stress in diet-induced obese Sprague-Dawley rats. Methods: Thirty weaning male rats were placed into three groups with 10 animals each: a control group with normal chow, a diet-induced obesity group (DIO) with high-fat diet, and an intervention group with high-fat diet supplemented with vitamin E (VE, 350 mg/kg). Blood and adipose tissue were collected from rats after 10 weeks. Biomarkers of oxidative stress were detected for plasma 8-epi-prostaglandin- F₂α (8-epi-PGF₂α), thiobarbituric acid-reactive substances (TBARS), total anti-oxidative capacity (TAOC), α-tocopherol, superoxide dismutase (SOD) activity, and glutathione peroxidase activity (GPx). Lipid and glucose metabolism parameters such as plasma glucose, insulin, and triacylglycerol (TG) were also analyzed. Results: After 10 weeks, all obese rats (both the DIO and VE groups) had higher plasma 8-epi-PGF_2α and TBARS levels than the controls. Their plasma-adjusted α-tocopherol, SOD, and GPx activities were lower than the control levels but insulin was higher (p<0.01). The VE intervention increased plasma SOD, GPx, and T-AOC, and decreased 8-epi-PGF_2α (p<0.05). VE intervention also decreased plasma glucose, insulin, and TG levels (p<0.05). Conclusions: Increased oxidative stress could be an important target for the prevention of obesity-related diseases. Vitamin E has moderate effects for improvement of oxidative stress status and glucose metabolism in the animal model of diet-induced obesity.