Histopathological and Ultrastructural Characterization of Lipofundin-Induced Atherosclerotic Lesions in Rabbits
Atherosclerosis is a disease of the vascular wall that leads to myocardial infarction, stroke, ischemia, gangrene and aneurysm. The primary lesion of atherosclerosis is an elevated focal plaque within the intima, with a central lipid core (mainly cholesterol and cholesterol esters) and a fibrous layer that covers it. The aim of this study was the histopathological and ultrastructural characterization of the atherosclerotic lesions induced in rabbits by the administration of Lipofundin 20%, a rich-lipid emulsion. Nineteen New Zealand rabbits were distributed in two groups. Group A (8 animals) only received intravenous injections of PBS and Group B (11 animals) received 2 mL / kg weight of Lipofundin 20% for 8 days. On day 9 animals were sacrificed and the aortic archs were isolated for histological and ultrastructural examination. In Group A, non-histopathology alterations were observed in the artery intima. However, all aorta samples from rabbits of Group B (treated with Lipofundin 20%) showed atherosclerotic lesions characterized by intima thickening, media-to-intima migration of vascular smooth muscle cells and an increased presence of proteoglycan and collagen fibers. In some samples the injured area was thicker than media layer. Ultrastructural analysis presence of large amounts of foam cells with lipid droplets at the intracellular level and abundant extracellular lipid droplets. These lesions were classified as Type III/ IV according to the classification of the Committee on Vascular Lesions of the American Heart Association.