Susceptibility to atherosclerosis in C57BL/6 mice. Atherosclerotic lesion areas (A) and number of lesions (B) in all groups of C57BL/6 mice fed a Western diet. Each point represents the average lesion area and mean number of lesions of four proximal aortic sections from each animal. Group means are indicated by horizontal bars. Average lesion areas and mean number of aortic lesions were similar in all groups of western-fed C57BL/6 mice (p = 0.32 and 0.29, respectively).