Protection by shear stress from collar-induced intimal thickening: role of nitric oxide.
Arterioscler Thromb Vasc Biol
; 19(11): 2609-14, 1999 Nov.
Article
em En
| MEDLINE
| ID: mdl-10559002
ABSTRACT
Nitric oxide (NO) has potent relaxant and antiproliferative effects on vascular smooth muscle cells, which may represent an important antiatherosclerotic mechanism. Since one of the major stimuli for NO release is flow-related shear stress, we have investigated (1) the effect of increased shear stress on neointimal formation induced in the rabbit carotid artery by enclosing the vessel in a nonconstrictive silicone soft collar and (2) the role of NO in the antiproliferative effect of increased shear stress. Forty-three New Zealand White rabbits were used. High shear stress in the left common carotid artery (CCA) was induced by ligature of the contralateral right internal carotid artery; intimal thickening was produced by the positioning a nonconstrictive silicone soft collar around the left CCA. To evaluate the role of NO, N(G)-nitro-L-arginine methyl ester (L-NAME) was orally administered at a subpressor dose. In all rabbits, arterial blood pressure, heart rate, arterial diameters, and blood flow velocities of both CCAs were determined at days 0, 3, 7, and 14. At the end of the study, all rabbits were euthanized, and histological analyses were performed on both CCAs of each animal. The presence of the collar was associated with a marked degree of intimal hyperplasia (intimal/medial area ratio 29+/-3.0% in collared arteries compared with 3+/-0.7% in sham control [noncollared] arteries, P<0.001). The increase in blood flow almost completely inhibited neointimal formation and induced an increase in arterial diameter of approximately 30%. The effects of increased blood flow were reversed by the administration of L-NAME. In conclusion, we demonstrate that in collar-induced intimal thickening, a chronic increase in shear stress (1) almost completely inhibits intimal thickening, and (2) this protective effect is mediated by NO production.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Artéria Carótida Interna
/
Óxido Nítrico
Tipo de estudo:
Diagnostic_studies
Limite:
Animals
Idioma:
En
Revista:
Arterioscler Thromb Vasc Biol
Assunto da revista:
ANGIOLOGIA
Ano de publicação:
1999
Tipo de documento:
Article