Although Apoe−/−Nba2.Yaa and Apoe−/− mice subject to a high cholesterol diet displayed similar atherosclerosis lesions size in aortic roots and abdominal aorta, the levels of macrophage and neutrophil infiltration, collagen, MMP-8 and MMP-9 and pro-MMP-9 expression in Apoe−/−Nba2.Yaa mice indicated features of atherosclerotic plaque vulnerability. Here, MMP9 is linked to atherosclerosis.