Resumen

SCORZA, T et al. Influencia de la administración a largo plazo de aceites de palma y maíz en la dieta sobre la vasoconstricción y vasodilatación arterial de la aorta del conejo. AVFT [online]. 2003, vol.22, n.2, pp.126-132. ISSN 0798-0264.

ABSTRACT Influence of long-term palm and corn oil diet supplement administration on rabbit aortic rings vasoconstriction and vasodilatation. The effect of long-term diet administration of palm and corn oil to rabbits was evaluated on plasma lipids and aortic rings reactivity to vasoconstrictor and endothelium- dependent and -independent vasodilator agents. Albino rabbits were divided into three groups, (n=12 each) fed with the following diets, Group I: standard chow diet (Conejarina®); Group II: standard diet with 10% palm oil; and Group III: standard diet with 10% corn oil, during 4 months. Rabbits blood samples were obtained at the beginning and at the end of the study; then the animals were anesthetized, the thoracic aorta extracted and cut in rings which were incubated in oxygenated Krebs solution to evaluate its reactivity to phenylephrine (PHE), acetylcholine (Ach) and sodium nitroprusside (SNP). Total plasma cholesterol increased after palm oil administration, from 20.4 to 35.1 mg/dL (p<0.05) and corn oil administration from 27.0 to 44.5 mg/dL (p<0.05). HDL-cholesterol increased in palm oil fed rabbits from 12.2 to 24.0 mg/dL (p<0.015). Corn oil did not modify HDL level but increased plasma triglycerides from 21.5 to 46.0 mg/dL (p<0.004). Ach DE-50, estimated from the dose-response curve (DRC) of control group (I) was 2.4 x 10^-7 mol/L; this curve was displaced to the left in the palm oil group and its DE-50 decreased to 7.5 x 10^-8 mol/L (p<0.05) and to 6.6 x 10^-8 mol/L (p<0.01) in the corn oil fed group. PHE reactivity of aortic rings did not change in the group receiving palm oil (p>0.05). In rabbits receiving corn oil, the DRC to PHE was significantly displaced to the right of the control group (p<0.05). NPS DRC did not change in aortic rings of rabbits receiving palm oil, and was significantly (p<0.01) displaced to the right of control curve in rabbits fed with corn oil. In conclusion, normocholesterolémic rabbits fed with palm oil supplement showed an increase of plasma cholesterol and particularly of its HDL fraction, and enhanced endothelium-dependent relaxation. Corn oil increased dependent- and independent-endothelial relaxation, and additionally blunted the vasoconstrictor response to a-adrenergic agonist agents.

Palabras clave : Palm oil; Corn oil; Vascular reactivity; Plasma lipids; apo-A-I; apo-B; C reactive protein.