Abstract
To evaluate the effect of EPA on arteriosclerosis, 24 Japanese white rabbits were studied as cuffsheathed models, which produced diffuse intimal thickening of the carotid artery. They were divided into 4 groups. Groups I and II were fed a normal diet, while groups III and IV were fed with a 0.5% cholesterol diet after cuff treatment. In groups I and III, EPA was administered p.o. forcibly at 600 mg/kg/day 1 week before cuff treatment. The cuff was placed around the carotid artery for three weeks. Then, carotid artery samples were obtained for pathological studies. From the elastica-stained samples, the area of the intima (AI), media (AM), and the part surrounded by the internal elastic lamella (A-IEL) were measured using a digitizer, to calculate AI/A-TEL (IT) and AI/AM (IT-M) as indices of intimal thickening.
The mean IT-M in group I (0.14) decreased significantly compared with group II (0.22), which showed cellulofibrous intimal thickening with a partly lacerated IEL. The mean IT in group III (0.30) was also significantly lower compared with group IV (0.46), which revealed prominent intimal thickening with spindleshaped smooth muscle cells. These findings suggested that EPA suppressed intimal thickening, with cell proliferation observed in the early phase of atherosclerosis.
