EFFECTS OF CHOLESTEROL LOADING ON AUTOIMMUNE MRL-LPR LPR MICE - SUSCEPTIBILITY TO HYPERCHOLESTEROLEMIA AND AORTIC CHOLESTEROL DEPOSITION/

Autoimmune MRL-lpr/lpr (MRL/l) mice, with a systemic lupus erythematos us-like disease, were shown to spontaneously develop hyperlipidemia an d yet be susceptible to diet-induced hypercholesterolemia and aortic c holesterol deposition. Control animals on a basal diet showed signific ant increases in the serum total cholesterol, phospholipids, triglycer ides, high density lipoprotein (HDL)-cholesterol and lipid peroxide le vels, but a significant decline in the serum lecithin:cholesterol acyl transferase (LCAT) activity compared to those of 5-week-old mice. Anim als on the high-cholesterol diet showed a rapid rise in serum total ch olesterol to a plateau level (800 mg/100 ml) that was approximately 2. 5 times higher than that in the control animals on a basal diet. Howev er, the levels of serum triglycerides, HDL-cholesterol and lipid perox ides significantly decreased (by 61%, 23% and 53%, respectively) compa red to those of the control animals, whereas LCAT activity and phospho lipid level were not affected. The aortic contents of total cholestero l, free cholesterol and cholesteryl ester were significantly higher (b y 35%, 36% and 31%, respectively) in animals fed the high-cholesterol diet than the control animals. These findings suggest that MRL/l mice are susceptible to diet-induced hypercholesterolemia and aortic choles terol deposition.