Foam cells generated by a combination of hyperglycemia and hyperlipemia in rats

Diabetes is a major risk factor for atherosclerosis, as well as hyperlipemia. Investigators have suggested that denatured lipoprotein in hyperglycemia transforms macrophages into foam cells, which correlates with the development or progression of atherosclerosis. In the present study, we examined the generation of foam cells in rats caused by a combination of hyperglycemia and hyperlipemia. Streptozotocin-induced diabetic male Wister rats were fed a high cholesterol diet (HCD) containing 1% cholesterol and 0.5% cholic acid to maintain a hyperglycemic and hyperlipemic state. Animals fed the HCD for 8 weeks or longer showed a high incidence of foam cell accumulation in the renal glomerulus, intima of aortic arch, splenic red pulp and marginal zone, liver sinusoid and intestinal lamina propria. The foam cells exhibited positive staining for antimonocyte/macrophage antibody and lipids in all these tissues. Anti-rat apolipoprotein B (apo B) antibody revealed that positive staining existed only in the cytoplasm of glomerular foam cells. These results suggest that the origin of these foam cells can be attributed to lipid-laden macrophages. The generation of foam cells in the hyperglycemia-hyperlipidemia supervening rat model presented in the present study might be a useful tool for investigations of the pathogenesis of foam cells.