a, Three-dimensional depiction of localization of DiI–oxLDL determined by confocal fluorescence microscopy of the luminal surface of the ascending aorta of Apoe−/−SR-B1fl/fl and Apoe−/−SR-B1∆EC mice. Red, DiI; blue, Hoechst staining of nuclei. b, Representative cumulative images of the x–y plane parallel to the luminal surface. c, Summation of DiI–oxLDL signal in the superficial ascending aorta. Two areas encompassing at least 100 cells each were counted per mouse in three mice per group for a total of n = 6 areas per genotype group. d, e, Uptake of DiI–oxLDL in the aorta. Human apolipoprotein B abundance (d) and DiI fluorescence intensity (e) were evaluated in aorta homogenates 4 h after intravenous DiI–oxLDL injection; n = 8 mice per group. f, g, Using the same approaches as in d, e, uptake of DiI–oxLDL in the aorta was evaluated in Apoe−/− mice treated with control or SR-B1-blocking antibodies given intraperitoneally before intravenous injection of DiI–oxLDL (n = 6 and 7 for control and anti-SR-B1 antibodies, respectively). h, Quantification of CD45+F4/80+ macrophages in the aorta (n = 6 aortas per group). Results are expressed relative to abundance in Apoe−/−SR-B1fl/fl control mice. i, Distribution of DiI–oxLDL in CD45+F4/80+ macrophages in the aorta; n = 6 mice per group. j, k, Uptake of DiI–nLDL in the aorta. Human apolipoprotein B abundance (j) or DiI fluorescence intensity (k) was evaluated in aorta homogenates 4 h after intravenous DiI–nLDL injection; n = 7 and 8 for Apoe−/−SR-B1fl/fl and Apoe−/−SR-B1∆EC mice, respectively. l, m, Using the same approaches as in j, k, uptake of DiI–nLDL in the aorta was evaluated in Apoe−/− mice treated with control or SR-B1 blocking antibodies given intraperitoneally before intravenous injection of DiI–nLDL (n = 5 mice per group). Left panels in d, f, j, l show representative immunoblots with three samples per group; data are mean ± s.e.m.; P values calculated by two-sided Student’s t-test. See also Supplementary Videos 1, 2.