Paper Information

Title: 

EXERCISE IMPROVES VASCULAR ENDOTHELIAL FUNCTION IN TYPE II DIABETIC MICE

Type: PAPER
Author(s): KHAZAEI MAJID,MOEIN AFSHARI F.,ESMAEIL L.
 
 
 
Name of Seminar: IRANIAN CONGRESS OF PHYSIOLOGY AND PHARMACOLOGY
Type of Seminar:  CONGRESS
Sponsor:  PHYSIOLOGY AND PHARMACOLOGY SOCIETY, MASHHAD UNIVERSITY OF MEDICAL SCIENCE
Date:  2007Volume 18
 
 
Abstract: 

Dysfunction of the endothelium is recognized precedes the vascular complications of diabetes. Exercise, an important first step in the management of type 2 diabetes, provides beneficial effects on the cardiovascular system by improving endothelial function. The mechanisms by which exercise confers such beneficial effects on vascular function are not well described. An additional aspect of lifestyle changes is management of weight so that the effects of exercise may be due to the concurrent effect on weight loss. To examine the vascular protective effects of lifestyle modifications in type 2 diabetes, we exercised db/db and wild type mice for one hour a day for five days a week. Mice were exercised either at low intensity (non-significant weight loss) or moderate intensity (10% weight loss) for 12 weeks. The aorta was removed for in vitro studies to determine endothelial cell function and measurements of Cu, Zn-SOD, Mn-SOD (antioxidant enzymes). Plasma extracts were used for assay of nitrite production (reflecting NO production) and 8-isoprostane (index of oxidative stress). Exercise (low- and moderate-intensity) improved endothelial cell function in the db/db mouse. Both exercise intensities also improved NO bioavailability by upregulating superoxide dismutase (SOD). Low-intensity exercise with no significant weight loss increased the expression of Cu, Zn-SOD (cytoplasmic), whereas moderate-intensity exercise causing a 10% weight loss enhanced Mn-SOD (mitochondrial) expression. There was no effect on catalase expression with either exercise protocol. Exercise reduced plasma levels of free radicals which may account for the restoration of NO bioavailabilty and improvements in vasodilatation. Based on our results we conclude that diabetic vascular dysfunction is accompanied by an enhanced oxidative environment, which reduces NO bioavailability and impairs endothelial function. Exercise up regulating SOD expression and increases NO mediated vasodilation. (Heart and Stroke Foundation of Canada).

 
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