Korean J Physiol Pharmacol.  2003 Feb;7(1):39-45.

Dietary Ascorbate Supplementation Reduces Oxidative Tissue Damage and Expression of iNOS in the Kidney of Streptozotocin Induced Diabetic Rats

• Choi MS
• Jang YY
• Lee WS
• Song JH
• Shin YK

Abstract

Reactive oxygen species (ROS) have been suggested to be contributory factors in complications of diabetes mellitus. In the present study, we investigated the generation of superoxide, the lipid peroxide level measured as thiobarbituric acid reactive substances, the vasorelaxation of isolated thoracic aorta and the iNOS expression in kidney of streptozotocin induced diabetic rats. Sprague Dawley rats were divided into four groups: control, ascorbate (400 mg/kg rat weight daily in drinking water), diabetic (single dose of 50 mg of STZ/kg i.p.) and diabetic simultaneously fed with ascorbate for 12 wk. Rats in groups were studied at tri-weekly intervals (0 to 12 wk). Diabetic rats were evaluated periodically with changes of plasma glucose levels and body weight. The ascorbate supplimentation attenuated the development of hyperglycemia and weight loss induced by STZ injection in rats. In the present experimental condition, the ascorbate supplimentation had no significant effect on plasma glucose levels and changes in body weight of normal rate. The superoxide generation, formation of thiobarbituric acid reactive substance and iNOS expression in kidney were significantly increased in STZ-treated rats that were decreased by ascorbate supplimentation. The ascorbate supplimentation had no effect on vasorelaxation of isolated thoracic aorta. These results indicate that ascorbate supplimentation may exert an inhibitory effect on STZ-induced oxidative tissue damage through protection of pancreatic islet cells by scavanging reactive oxygen species. The ascorbate supplimentation may possibly attenuate the renal complication of diabetes mellitus.

Keyword

Ascorbate; iNOS; Streptozotocin

MeSH Terms

Animals
Aorta, Thoracic
Blood Glucose
Body Weight
Diabetes Complications
Diabetes Mellitus
Drinking
Hyperglycemia
Islets of Langerhans
Kidney*
Rats*
Rats, Sprague-Dawley
Reactive Oxygen Species
Streptozocin*
Superoxides
Thiobarbituric Acid Reactive Substances
Vasodilation
Weight Loss
Reactive Oxygen Species
Streptozocin
Superoxides
Thiobarbituric Acid Reactive Substances