Abstract
Objective: Endothelial dysfunction is a key element in the pathogenesis of atherosclerosis in humans, which is associated with hypercholesterolemia and hypertension. The spontaneously hypertensive rat (SHR) is one of the most widely studied animal models for human essential hypertension. Interestingly, it was shown that the total plasma cholesterol concentration in SHR rats does not differ from that of normotensive Wistar-Kyoto rats (WKY) (1). However, the cholesterol concentration in the SHR liver is little known. Therefore, the aim of this study was to examine endothelium-dependent acetylcholine (ACh)-induced relaxation in the femoral artery (FA) and the content of cholesterol in the liver of 22-week-old WKY and SHR rats. Design and Method: Blood pressure (BP) was determined by tail-cuff plethysmography. To evaluate the degree of cardiac hypertrophy, weight of wet mass of the left heart ventricle (LVW) was determined in order to calculate their relative weight (LVW/tibial length). Samples of liver tissues were used for cholesterol determination (2). ACh-induced relaxation was investigated in rings of the FA, with the wire myograph. Since vasorelaxation, expressed as a percentage of pre-constriction, was inversely related to initial tension, relaxing responses were expressed as absolute values (mN/mm) too. Results: BP of WKY and SHR was 111 ± 3 and 184 ± 6 mm Hg, respectively (p < 0.001). There was significant increase in the relative left ventricle weights in SHR vs. WKY (p < 0.001). Concentrations of cholesterol were similar in WKY and SHR livers. Relative and absolute ACh-induced relaxation was reduced in SHR vs. WKY. Conclusions: We supposed that the endothelial dysfunction in SHR rats is not associated with the derangement in the cholesterol synthesis in the liver.
Published Version
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