Recent studies of the relation between serum
triacylglycerol concentration and the risk for
coronary artery disease suggest that inefficient clearance of postprandial
triacylglycerols promotes
atherogenesis. We recently demonstrated that dietary
diacylglycerol (DAG), rich in the 1,3-species, suppresses the postprandial increase in serum
triacylglycerol levels compared with dietary
triacylglycerol (TAG). Here, we investigated the effects of dietary DAG on
atherosclerosis in rabbits with
cholesterol-induced
atherosclerosis. New Zealand White rabbits (n = 20) were fed a diet containing 3%
lard and 1.3%
cholesterol for 50 d to induce atherosclerotic lesions. Thereafter, the rabbits were assigned to 2 groups and fed 90 g/d nonpurified diet and orally administered 5 g DAG or TAG for an additional 34 d. Reference rabbits (n = 5) were fed only the nonpurified diet throughout the 84-d study. The area of atherosclerotic lesions and aortic
lipid concentrations were significantly lower in DAG-fed rabbits compared with TAG-fed rabbits. The
VLDL receptor and macrophage antigen-1
mRNA expression levels were significantly lower in DAG-fed rabbits than in TAG-fed rabbits. In the liver of DAG-fed rabbits, the
triacylglycerol concentration was lower and the
carnitine palmitoyltransferase activity higher than in TAG-fed rabbits. Stimulation of hepatic
lipid catabolism might be related to the reduced
lipid accumulation in the liver and aorta by reducing the release of
triacylglycerol into the circulation. Thus, long-term consumption of DAG, which reduces postprandial
lipemia, might be useful for the regression of
atherosclerosis by stimulating hepatic
lipid catabolism and thereby modulating monocyte/macrophage migration and aortic
lipid accumulation.