Date of Award

2005

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Environmental Science

First Advisor

Dr. Ernest Adeghate

Second Advisor

Dr. Emmanuel C. Opara

Third Advisor

Abdu Adem

Abstract

Diabetes mellitus is recognized as one of the leading causes of morbidity and mortality in the world. About 5 to 6% of the world population suffers from this disease and the number of people diagnosed with diabetes is rapidly increasing. Diabetes has been demonstrated to be associated with oxidative stress and hyperglycemia, one of the most important indictors of oxidative stress. Normally the endogenous mechanisms of enzymes and antioxidants are able to destroy the reactive species and create a balance between antioxidant and free radicals. In diabetes, the oxidative stress is increased due to the deficiency in the antioxidant defense. The intake of antioxidants such as vitamin E and C may reduce the oxidative stress associated with diabetes and hence help to restore the antioxidant defense system.

The aim of this study is to investigate the effect of different doses of either vitamin E or C on the metabolic and biochemical parameters of normal and streptozotocin (STZ)-induced diabetic rats. Biochemical analysis, immunohistochemistry, and radioimmunoassay techniques were used to study the effect of these vitamins on the metabolic and biochemical parameters of normal and diabetic rats. The result of this study revealed that the oral administration of vitamin E and C significantly reduced the body weight gain in a dose-correlated manner. Moreover, vitamin E and C significantly

(p<0.0001) reduced the blood glucose level in normal (p

Moreover, the kidney function of normal and diabetic rats was affected after the oral administration of vitamin E and C. High dose of vitamin C significantly (p<0.01) increased the blood urea nitrogen level of diabetic rats, while low dose of vitamin E significantly increased (p<0.03) blood urea nitrogen of normal rats. The plasma level of electrolytes such as calcium and sodium also changed significantly (p<0.00001) after oral administration of either vitamin E or C.

In an immunohistochemical study of pancreas on the number and distribution of insulin and glucagon cells, a significant increase in the number of insulin positive cells was observed in rats treated with vitamin E and C after the onset of diabetes when compared to control. However, the number was still significantly less than that obtained for control normal rats.

However, both vitamin E and C fail to increase the insulin level of normal and diabetic rats. The level of plasma glucagon increased after the onset of diabetes mellitus and both of vitamin E and C significantly reduced its level in diabetic rats when compared to control.

In conclusion antioxidants such as vitamin E and C may ameliorate the metabolic and biochemical parameters of diabetic rats.

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