|M.Sc Student||Shen Michal|
|Subject||The Effects of Diabetes Mellitus on Lipid Peroxidation in|
Organs (Heart, Uterus, Skeletal Muscle, Liver,
Kidney), and the Response of these
Organs to Estrogen Treatment
|Department||Department of Medicine||Supervisors||Assistant Professor Yoram Kanter|
|Dr. Nitsa Mirsky|
Diabetes mellitus increases the risk for CVD in women. Recent data showed increased oxidative stress in diabetes. While there is considerable evidence suggesting beneficial effects of estrogen on decreasing lipid peroxidation, atherosclerotic processes and cardiovascular diseases, diabetes negates most estrogen protective effects. In the present study, we examined the in vivo effects of 17b-estradiol (E2), on lipid peroxidation and antioxidant defense systems in several organs. Healthy or diabetic SPD female rats were injected with either E2 (10, 20, or 50 mg/rat) or with vehicle. Twenty-four hours following the injection, the animals were sacrificed. Their organs were removed and assayed for lipid peroxidation, using TBARS assay, antioxidative capacity, by measuring catalase activity and the level of free thiol compounds. TBARS level was higher in heart, skeletal muscle and uterus derived from diabetic animals, compared to healthy control animals. E2 injection decreased TBARS level in both healthy and diabetic hearts, but the sensitivity to E2, was much higher in healthy hearts, indicating a decreased sensitivity to estradiol in diabetic cardiac tissue. Similar reduced sensitivity to E2 was demonstrated for diabetic uterus and skeletal muscle. Although no significant difference in TBARS level was observed in liver and kidney from either healthy or diabetic rats, the sensitivity to E2 treatment was higher in healthy organs. Catalase activity and free thiol compounds in diabetic heart, uterus and skeletal muscle was much higher than in organs from healthy rats, indicating a failure of the antioxidant defense systems in diabetic organs to combat elevated peroxidation processes. E2 treatment reduced the elevated in catalase activity and free thiol compounds in organs from diabetic rats tested. In summary, diabetes mellitus alters the ability of different organs to resist lipid peroxidation, and attenuates E2 inhibition of oxidation processes.