Abstract
We studied the elasticity and endothelium-dependent relaxation (EDR) of the aorta in 1% cholesterol diet (HCD)-fed rabbits. Furthermore, the effects of ethyl all-cis-5, 8, 11, 14, 17-icosapentaenoate (EPA-E) were examined in this model of atherosclerosis. After 12 weeks of feeding with HCD, the animals showed increase in plasma total cholesterol level, formation of atherosclerotic plaque, decrease in aortic elasticity and impairment of EDR to acetylcholine (ACh). The levels of aortic elasticity in HCD-fed rabbits administered orally with EPA-E (300 mg/kg for 12 weeks) were almost the same as those of rabbits fed a normal diet, although EPA-E showed no effects on the plasma total cholesterol level and formation of atherosclerotic plaque in HCD-fed rabbits. On EDR in response to ACh and cyclic GMP formation in the HCD-fed rabbit aorta, EPA-E improved the impairment of these parameters, but not significantly. Therefore, EPA-E had little effect on the endothelium in this model of atherosclerosis, although EPA-E improved the decrease in the aortic elasticity. Because the levels of aortic elasticity showed no significant correlation with the magnitude of EDR to ACh or the size of atherosclerotic plaque, the decrease of aortic elasticity in this model of atherosclerosis was thought to have little relation to the dysfunction of the endothelium.
