Morphologic characterization of aortic plaques at valvular inset level in ompK36-immunized ApoE−/− and control mice.
(A) Representative Oil red O (original magnification X40) and Sirius red (original magnification X10) images of aortic atherosclerotic plaques and quantification of the average lipid, collagen and calcification content by morphometry. Lipid, collagen and calcification areas were measured in at least five sections/mouse in 5 mice/group and were normalized on the total plaque area of each section. (B) Representative fields of aortic root sections stained with either anti-CD68 (green) or anti-Arginase I (red) (original magnification X40); quantification of total cell density, CD68+ cells and ArgI+ cells are shown in the below histograms. Positive cells were counted in at least two sections/mouse and in at least 5 mice/group. Total plaque cells/plaque area were assessed and the percentage of CD68+ cells/total cell number calculated, while percentage of ArgI+ cells was calculated out of CD68+ cell number. Data are presented as mean ± s.e.m. (n = 5/group). Statistical analysis: unpaired student t test. *P < 0.05.