Lipid-lowering treatment in a rabbit model of atherosclerosis: a vessel wall magnetic resonance imaging study

BACKGROUND: Vessel wall magnetic resonance imaging (VWMRI) is currently one of the best imaging techniques for the non-invasive evaluation of intracranial atherosclerotic lesions. However, it is still impossible to obtain pathological specimens of intracranial atherosclerotic plaques in vivo. The establishment of experimental animal models of atherosclerotic lesions similar to those of humans could solve this deficiency. METHODS: A model of abdominal aortic atherosclerosis in New Zealand white rabbits was established using abdominal aortic balloon dilatation combined with high-fat fodder. The pathological results were used as the reference standard for the successful establishment of the animal model. The rabbits with abdominal aortic atherosclerosis were randomly divided into the lipid-lowering treatment and the normal-fodder control groups. VWMRI and blood biochemical examinations were performed at 4, 12, and 24 weeks, and the radiologic-pathologic correlations were established. RESULTS: A rabbit abdominal aortic atherosclerosis model was established using balloon dilatation followed by high-fat fodder for 8 weeks. The lipid-lowering treatment reduced the plaque lipid core volume and decreased the plaque burden. However, it did not change plaque distribution, shape, or reverse vascular remodeling. Our pathological findings suggest that the lipid-lowering treatment reduced intraplaque macrophages but did not alter microvascular density. CONCLUSIONS: VWMRI accurately assessed the morphological changes of the plaques before and after the lipid-lowering treatment, and the results support the pathology results. VWMRI could be useful in experimental studies on the pathogenesis, diagnosis, and treatment of atherosclerotic lesions.