Assessment of in vivo Aortic Wall Characteristics at the Early Stage of Atherosclerosis in Rabbits

Assessment of in vivo Aortic Wall Characteristics at the Early Stage of Atherosclerosis in Rabbits

Creators Hironaka Katsumi

To assess wheter vascular responsiveness to α-receptor agonist is altered or not at the early stage of atherosclerosis, in vivo aortic pressere-diameter relationship of aorta over a wide range of pressere was analyzed before and after the acute administration of α-receptor agonist (phenylephine) in 9 hyper cholesterolemic fat-fed (7 weeks) rabbits and 8 normal diet-fed (7 weeks ) rabbits. There was no significant difference in the aortic wall thickness between both groups, suggesting the early stage of atherosclerosis. Using a modified three element Max well model, diastolic stress-strain relationship was computed after applying several assumptions to the astual aortic pressure-diameter relationship. After the intravenous administration of phenylephrine at a rate of 5 mg/ kg/ min, the atress (ordinate)-atrain (abscissa) relation curves were shifted to the left, indicating the activation of aortic smooth muscle by phenylephrine. The difference in the stress before and after phenylephrine infusion showed a single peak at a certain strain. The peak difference in the stress was smaller in hypercholesterolemic fat-fed rabbits than in normal diet-fed rabbits, indicating the decreased vascular responsiveness at the early stage of atherosclerosis.

[ISSN]0513-1812

[NCID]AA00594272