Macrophage scavenger receptor (SR-A I/II) deficiency reduced diet-induced atherosclerosis in C57BL/6J mice.

The effects of SR-A I/II deficiency and a synthetic anti-oxidant BO-653 on a diet-induced atherosclerosis in C57BL/6J, an inbred strain known to be susceptible to diet-induced atherosclerotic lesion formation, were examined. Quantitative analysis of the extent of atherosclerotic lesions in the mice fed the high-fat diet revealed that the atherosclerotic lesion area in SR-A I/II mutants was significantly reduced by 70% compared to wild type mice. A similar level of lesion reduction (75%) was found in wild type mice fed the high-fat diet supplemented with 0.6% BO-653 compared to those without BO-653. Thus, for C57BL/6J in the setting of prolonged exposure to a high-fat diet, defect of SR-A I/II expression is significantly protective against the development of atherosclerosis, as is the synthetic anti-oxidant BO-653. These results indicate that SR-A I/II has a crucial role in atherosclerotic lesion formation with uptake of oxidized-LDL in this mouse model.