Effects of a high-cholesterol diet on arterial wall thickness and vascular reactivity in young rabbits.

Cholesterol enrichment of arteries may induce biochemical and structural abnormalities in vascular smooth muscle resulting in increased arterial contractile sensitivity. We studied the effects of a high-cholesterol diet on arterial structural properties and vascular reactivity in young rabbits. In vivo measurements of aortic intimal-plus-medial thickness using high resolution ultrasound imaging were obtained before and after 3 weeks of a high-cholesterol diet in 12 rabbits (group 2) and compared to data from 12 animals a cholesterol-free diet fed (group 1). Six rabbits (group 3) were studied before and after a 3-week, high-cholesterol diet and after a subsequent 13-week, cholesterol-free recovery diet. Blood pressure responsiveness to noradrenaline was evaluated before and at the end of each diet period. In groups 2 and 3, high dietary cholesterol caused an increase in intimal-plus-medial thickness from 0.31 mm and 0.33 mm to 0.88 mm and 0.89 mm, respectively (p less than 0.001). Plasma cholesterol concentration rose from 0.9 +/- 0.26 mmol/l to 36.7 +/- 8.56 mmol/l. There was no change in group 1. In group 3, intimal-plus-medial thickness remained increased (1.01 mm) following the cholesterol-free recovery diet despite normal plasma cholesterol. Blood pressure responsiveness to noradrenaline was markedly increased after the high-cholesterol diet (p less than 0.001) in groups 2 and 3 and after the cholesterol-free recovery diet in group 3 (p less than 0.001), and was directly related to intimal-plus-medial thickness (r = 0.84; p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)