LIPID-PEROXIDATION AND CEROID ACCUMULATION IN MACROPHAGES CULTURED WITH OXIDIZED LOW-DENSITY-LIPOPROTEIN

When mouse peritoneal macrophages were cultured with oxidized human lo w density lipoprotein (ox-LDL), storage of ceroid-like pigments was ob served within the cells by light and fluorescent microscopy, and fluor escence spectrophotometry. The fluorescent products exhibit the charac teristics of Schiff base structures, having a fluorescence maximum of 430 nm and an excitation maximum of 355 nm, which has been generally a ccepted with fluorescent lipid peroxidation products. Similar fluoresc ent products were isolated from the atherosclerotic lesions of the age d human artery. Ox-LDL was also intraperitoneally injected into guinea pigs to study an early stage of ceroid accumulation in macrophages. A n early event In guinea pigs was the appearance of neutrophils. The fi ndings from the model systems suggest that the ox-LDL in the artery wa ll is probable chemotactic for neutrophils as well as monocytes. We pr opose the hypothesis that the production of superoxide by neutrophils causes further lipid peroxidation of native LDL and then produces larg e amounts of oxidatively modified LDL which is the souse of ceroid pig ment accumulated within the foam cells in human atherosclerotic lesion s.