Abstract
It is noted that there are two types of WHHL rabbits; the one with high incidence of coronary atherosclerosis (type 1), and the other with low incidence of coronary atherosclerosis (type 2). In order to analyze the difference between type 1 and type 2 WHHL rabbits, in this study, the atherogenesity of some classes of lipoproteins were estimated by incubation with mouse peritoneal macrophages.
Among the several classes of lipoproteins, VLDL from type 1 WHHL rabbit could stimulate cholesteryl [14C]-oleate synthesis 10.5 fold than did VLDL from type 2 WHHL rabbit. VLDL from normal rabbit showed no significant stimulatory effect. LDL did not stimulate esterification of cholesterol in macrophages, unless it became modified form.
Mass ratios (cholesterol/protein) of these lipoproteins were calculated for their characterization. The calculated ratios of β-VLDL, VLDL from type 1 WHHL rabbit, from type 2 WHHL rabbit and from normal rabbit were 13.6, 5.69, 2.05 and 0.82, respectively.
These data suggest that the high incidence of coronary atherosclerosis in type 1 WHHL rabbit is partially due to the cholesteryl ester rich VLDL, and that the atherosclerosis observed in WHHL rabbit is caused not only by high concentration of plasma LDL, but also by cholesteryl ester rich VLDL.
