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)

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 > School of Cardiovascular & Metabolic Health
• Journal Name: Hypertension
• ISSN: 0194-911X
• ISSN (Online): 1524-4563