Distribution of selected elements in atherosclerotic plaques of apoE/LDLR-double knockout mice assessed by synchrotron radiation-induced micro-XRF spectrometry

Apolipoprotein E and LDL receptor double-knockout (apoE/LDLR-/-) mice represent a reliable experimental model of atherosclerosis. The aim of the present study was to examine the elemental content of atherosclerotic plaques using synchrotron radiation-induced micro x-ray fluorescence (XRF) spectrometry. Numerous essential and trace elements were detected in cross-sections of aortic roots collected from 6-month-old apoE/LDLR-/- mice fed with chow diet. Two-dimensional maps of the elemental distribution and point recordings were compared with images of consecutive sections stained histologically, allowing precise localization of the analyzed elements in morphologically defined areas of aortic lesion. The sulphur was detected in areas occupied by macrophages and smooth muscle cells. Iron was observed in high concentrations in cardiac and smooth muscle, blood clots and in adjacent coronary vessels. Lower concentrations of iron were seen in the regions of plaques rich in macrophages and lipids. Copper was detected in higher amounts only in cardiac muscle and its concentration in plaques was very low. There was a quite high content of calcium in aortic plaque areas containing lipids and macrophages. Much higher concentrations of calcium were observed in mineral deposits, mostly located in the aortic media. Similar distribution was also characteristic for phosphorus. Zinc was observed in moderately low concentrations in atheromas. Higher content of zinc was seen in smooth musculature, in cardiac muscle and in mineral concretions. The presented results provide a substantial morphological and physicochemical background for further investigations aiming to evaluate pharmacological and dietary treatment of atherosclerosis in an apoE/LDLR-/- mouse model. Copyright (c) 2008 John Wiley & Sons, Ltd.