Effects of Subchronic Exposures to Concentrated Ambient Particles (CAPs) in Mice: V. CAPs Exacerbate Aortic Plaque Development in Hyperlipidemic Mice

AbstractRecent epidemiological studies suggest that long-term exposure to particulate matter (PM) causes chronic effects on the cardiovascular system that result in cumulative increases cardiovascular morbidity and mortality. Since atherosclerosis is a progressive irreversible condition and an underlying cause of many cardiovascular diseases, we hypothesized that long-term exposure to PM causes adverse cardiovascular effects by exacerbating atherosclerosis. In this study, we exposed C57- and ApoE-deficient (ApoE−/−) and ApoE, LDLr (DK)-deficient mice to concentrated ambient PM2.5 for 6 h/day, 5 days/wk, for up to 5 mo. The overall mean exposure concentration for these groups of animals was 110 μ g/m3. The cross-sectional area of the aorta root of DK mice was examined morphologically using confocal microscopy for the severity of lesion, extent of cellularity, and lipid contents. Aortas from the arch to the iliac bifurcations were also sectioned longitudinally and lesion areas were stained with Sudan IV. Al...