Fig. 2.

Morphology of apoE^−/− and apoE^−/−xTg^SMC-Cat aortas at baseline. A: total collagen content per aortic dry weight decreased by 41% in apoE^−/− compared with apoE^−/−xTg^SMC-Cat. B: apoE^−/− adventitia thickness was 32% less than apoE^−/−xTg^SMC-Cat. C and D: representative images of the aortic wall stained with picrosirius red and imaged under polarized light. ApoE^−/− image shows red and green illumination indicating presence of type I and type III collagen, respectively. ApoE^−/−xTg^SMC-Cat aortic cross section showed intense red illumination indicating a greater abundance of type I collagen. E: elastin fragmentation in the abdominal aortic wall was greater in apoE^−/− compared with apoE^−/−xTg^SMC-Cat aortas. Elastin fragmentation was expressed as the number of breaks in elastic laminae per medial area. Medial area was defined as the area enclosed by the inner and outer elastic laminae measured from aortic sections. *P < 0.05; n = 5 for apoE^−/−; n = 3 for apoE^−/−xTg^SMC-Cat.