Antioxidant effects of vitamins C and E are associated with altered activation of vascular NADPH oxidase and superoxide dismutase in stroke-prone SHR

Chen, X., Touyz, R.M. , Park, J.B. and Schiffrin, E.L. (2001) Antioxidant effects of vitamins C and E are associated with altered activation of vascular NADPH oxidase and superoxide dismutase in stroke-prone SHR. Hypertension, 38(3), pp. 606-611. (doi:10.1161/hy09t1.094005)

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Publisher's URL: http://dx.doi.org/10.1161/hy09t1.094005

Abstract

Ascorbic acid (vitamin C) and α-tocopherol (vitamin E) have antioxidant properties that could improve redox-sensitive vascular changes associated with hypertension. We determined whether vitamins C and E influence vascular function and structure in hypertension by modulating activity of NADPH oxidase and superoxide dismutase (SOD). Adult stroke-prone spontaneously hypertensive rats (SHRSP) were divided into 3 groups: control (C; n=6), vitamin C-treated (vit C, 1000 mg/day; n=7), and vitamin E-treated (vit E, 1000 IU/day; n=8). All rats were fed 4% NaCl. Blood pressure was measured weekly. After 6 weeks of treatment, the rats were killed, and mesenteric arteries were mounted as pressurized preparations. Vascular O2− generation and NADPH oxidase activity were measured by chemiluminescence. Vascular SOD activity and plasma total antioxidant status (TAS) were determined spectrophotometrically. Blood pressure increased from 212±7 to 265±6 mm Hg in controls. Treatment prevented progression of hypertension (vit C, 222±6 to 234±14 mm Hg; vit E, 220±9 to 227±10 mm Hg). Acetylcholine-induced vasodilation was improved (P<0.05), and media-to-lumen ratio was reduced (P<0.05) in the treated rats. O2− was lower in vitamin-treated groups compared with controls (vit C, 10±4 nmol · min−1 · g−1 dry tissue weight; vit E, 9.6±3.5 nmol · min−1 · g−1 dry tissue weight; C, 21±9 nmol · min−1 · g−1 dry tissue weight; P<0.05). Both vitamin-treated groups showed significant improvement (P<0.01) in TAS. These effects were associated with decreased activation of vascular NADPH oxidase (vit C, 46±10; vit E, 50±9; C, 70±16 nmol · min−1 · g−1 dry tissue weight, P<0.05) and increased activation of SOD (vit C, 12±2; vit E, 8±1; C, 4.6±1 U/mg; P<0.05). Our results demonstrate that vitamins C and E reduce oxidative stress, improve vascular function and structure, and prevent progression of hypertension in SHRSP. These effects may be mediated via modulation of enzyme systems that generate free radicals.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Touyz, Professor Rhian
Authors: Chen, X., Touyz, R.M., Park, J.B., and Schiffrin, E.L.
College/School:College of Medical Veterinary and Life Sciences > Institute of Cardiovascular and Medical Sciences
Journal Name:Hypertension
ISSN:0194-911X
ISSN (Online):1524-4563

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