Publications (2)4.18 Total impact
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ABSTRACT: Diabetics and experimental animal models exhibit high oxidative stress due to persistent and chronic hyperglycemia, thereby deplete the activity of the antioxidative defense system and thereby promote the generation of free radicals. The current study examined the effects of vitamin E on oxidative stress and membrane fluidity in the brain of diabetes-induced rats. Sprague-Dawley male rats were randomly assigned to normal and streptozotocin (STZ)-induced diabetic groups. The diabetic groups were fed a vitamin E-free diet, 40 mg vitamin E/kg diet, or 400 mg vitamin E/kg diet. Diabetes was induced with STZ after 3 weeks of the experimental diet, then the rats were sacrificed 9 days later to determine the oxidative stress and cell membrane fluidity in the brain. Dietary vitamin E strengthened the antioxidative defense system with an increased activity of the antioxidant enzymes, such as superoxide dismutase (SOD) and glutathione peroxidase (GSH-px) and increased vitamin E content, in the brain of the diabetes-induced experimental rats. Accordingly, vitamin E was found to reduce the accumulation of reactive oxygen species (ROS), such as superoxide radical decrease the generation of oxidative damage substances, such as the carbonyl value, increase the membrane fluidity lowered by oxidative damage, and significantly improve the lipid composition. Vitamin E was found to be excellent for strengthening the antioxidative defense system, reducing the generation of ROS and damaging oxidative substances, and maintaining membrane fluidity in the brain of diabetes-induced rats.
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ABSTRACT: The purpose of the present study was to investigate the effects of green tea catechin on prostaglandin synthesis of renal glomerular and renal dysfunction in rats with streptozotocin−induced diabetes. Sprague-Dawley rats weighing 100 ± 10 g were randomly assigned to one normal group and three groups with streptozotocin-induced diabetes. The diabetic groups were classified to a catechin-free diet (DM group), a 0.25% catechin diet (DM-0.25C group) and a 0.5% catechin diet (DM-0.5C group) according to the levels of catechin supplement in their diet. The animals were maintained on an experimental diet for 4 weeks. At this point, they were injected with streptozotocin to induce diabetes. They were killed on the sixth day. The catechin supplementation groups (DM-0.25C, DM-0.5C groups) showed a decrease in thromboxane A2 synthesis but an increase in prostacyclin synthesis, compared to the DM group. The ratio of prostacyclin/thromboxane A2 was 53.3% and 38.1% lower in the DM and DM-0.25C groups, respectively, than in the normal group. The ratio in the DM-0.5C group did not differ from that in the normal group. The glomerular filtration rate in catechin feeding groups (DM-0.25C and DM-0.5C groups) was maintained at the normal level. The urinary β2-microglobulin content in the DM-0.5C group was significantly lower than that in the normal group. On the sixth day after induction of diabetes, the urinary microalbumin content in the DM, DM-0.25C and DM-0.5C groups had increased 5.40, 4.02, 3.87 times, respectively, compared with the normal group. In conclusion, kidney function appears to be improved by green tea catechin supplementation due to its antithrombotic action, which in turn controls the arachidonic acid cascade system.