ISSN:
1432-0428
Keywords:
Keywords Vitamin E
;
ascorbic acid
;
oxidative stress
;
isoprostanes
;
nitric oxide
;
vascular endothelium
;
resistance artery
;
diabetes mellitus.
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary Impaired endothelium-dependent relaxation could underlie many of the vascular complications associated with insulin-dependent diabetes mellitus, and may be mediated by increased oxidative stress. The effect of antioxidants on vascular endothelial function and oxidative stress of streptozotocin-diabetic rats was assessed by dietary supplementation with vitamins E and C. Diabetic (i. v. streptozotocin, 45 mg/kg) male Sprague-Dawley rats were fed one of six supplemented diets containing 75.9, 250, or 500 mg vitamin E/kg chow, 250 mg vitamin C/kg H20, 250 mg vitamin E/kg chow plus 250 mg vitamin C/kg H2O, or chow deficient in vitamin E, and then compared to standard-fed control rats. After 4 weeks, small mesenteric arteries were dissected and mounted on a small vessel myograph, concentration response curves were then constructed to noradrenaline, acetylcholine and sodium nitroprusside. Acetylcholine-mediated relaxation was impaired in arteries from diabetic rats (pEC50 6.701 ± SEM 0.120, n = 8) compared to controls (7.386 ± 0.078, n = 6; p 〈 0.05). The 500 mg/kg vitamin E diet further impaired maximum relaxation to acetylcholine (58.2 ± 10.5 vitamin E, n = 7 vs 84.4 ± 5.3 % standard, p 〈 0.05), and the combined vitamin E plus C diet impaired maximum relaxation to sodium nitroprusside (48.5 ± 4.1 in vitamin E + C, n = 8 vs 75.6 ± 3.9 % standard; p 〈 0.01). However, plasma 8-epi-prostaglandin (PG)F2α (measured as an estimate of oxidative stress) was dose-dependently decreased in rats on vitamin E supplemented diets. Dietary antioxidant supplementation did not reverse impaired endothelial function in this model of uncontrolled diabetes despite a concomitant decrease in oxidative stress. [Diabetologia (1998) 41: 148–156]
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s001250050883
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