Coronary wall imaging in mice using osmium tetroxide and micro-computed tomography

Coronary artery disease (CAD) is a major cause of death in the United States and results from the accumulation of atherosclerotic plaques in the arteries of the heart. Plaques accumulate as the result of the retention of low-density lipoprotein (LDL) particles in the sub-endothelium of the arterial wall. In mouse aorta, these lesions form primarily at the branching sites or bifurcations. However, in the coronary system, data has shown that late-stage plaque formation occurs throughout the proximal segments of the arteries. In order to better understand plaque formation in the coronary arteries, we have developed an osmium tetroxide (OsO4) stained coronary wall imaging protocol performed using microcomputed tomography (microCT). OsO4 is a heavy metal contrast agent that readily binds to lipids. Our data in 3- to 25-week old C57BL6 wild-type mice shows that the coronary vessel walls are highlighted by the use of the contrast agent. We expect that this combination of OsO4 and microCT will allow us to investigate the coronary artery wall in atherogenesis models of mice to characterize plaque formation.