Efeitos da vitamina E sobre o fluxo coronario endotelio-dependente em cães hipercolesterolemicos

AUTOR(ES)

Luiz Antonio Abdalla

DATA DE PUBLICAÇÃO

2002

RESUMO

The effects of vitamin E on endothelium-dependent coronary flow were studied in hypercholesterolernic dogs. Adult mongrel dogs weighing 7.4±1.0 kg were divided into control, hypercholesterolernic and vitamin E groups. The animals in the hypercholesterolernic group were fed a diet enriched with cholesterol (5%w/w) and coconut oil (l0%w/w) for 40 days. The vitamin E group received the same diet plus 400 IU of vitamin E during the last 15 days of the experiment. Total serum cholesterol levels were evaluated at the beginning and at the end of the experiment using a commercial enzyme kit and a Beckman analyzer. The coronary flow was determined byelectromagnetic flowmetry using a probe positioned in the left anterior descending coronary artery, near the ostium. A needle connected to a perfusion pump was introduced into the coronary artery for the administration of acetycholine and sodium nitroprusside at a rate of 5 ug!kg per min. The aorta was cannulated for the measurement of arterial blood pressure via a pressure transducer coupled to a Siemens multi-channel recorder. The tissue cholesterol content and malonic dialdehyde (MDA) were also measured in isolated coronary vessel specimens. At the end of 40 days, the serum cholesterol levels had increased by 203% and 198% in the hypercholesterolernic and vitamin E groups, respectively. However, the difference in the levels of these two groups was not significant (P>0.05). The aortic blood pressure and heart rate remained inchanged during acetylcholine administration. In contrast, systolic and diastolic pressure fell and the heart rate increased during the infusion of sodium nitroprusside. The tissue cholesterol content and MDA were significantly (P<0.05) increased in coronary artery specimens from the hypercholesterolernic compared to control animals. Vitamin E was able to reduce these increases in cholesterol treated animals (P<0.O5). The percent change in coronary flow during acetylcholine administration was significantly lower in the hypercholesterolernic group when compared with control animals (P<0.05) but was unaltered in the vitamin E group (P>0.05). During sodium nitroprusside administration, the coronary flow increased in the vitamin E group (P

ASSUNTO(S)

endotelio arterias coronarias colesterol acetilcolina

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