Structural and biomechanical alterations in rabbit thoracic aortas are associated with the progression of atherosclerosis
1 Cardiothoracic Surgery Department, University Hospital of Patras, 26504 Patras, Greece
2 Laboratory of Biomechanics and Biomedical Engineering, Department of Mechanical Engineering and Aeronautics, University of Patras, 26504, Patras, Greece
3 Anatomy Department, University of Patras, 26504 Patras, Greece
4 Department of Anaesthesiology and Critical Care Medicine, University Hospital of Patras, 26504 Patras, Greece
5 Biochemistry Department, University Hospital of Patras, 26504 Patras, Greece
6 Experimental Research Center, ELPEN Pharmaceuticals, Marathonos 95 str, 19009 Athens, Greece
Lipids in Health and Disease 2011, 10:125 doi:10.1186/1476-511X-10-125Published: 26 July 2011
Atherosclerosis is a diffuse and highly variable disease of arteries that alters the mechanical properties of the vessel wall through highly variable changes in its cellular composition and histological structure. We have analyzed the effects of acute atherosclerotic changes on the mechanical properties of the descending thoracic aorta of rabbits fed a 4% cholesterol diet.
Two groups of eight male New Zealand White rabbits were randomly selected and fed for 8 weeks either an atherogenic diet (4% cholesterol plus regular rabbit chow), or regular chow. Animals were sacrificed after 8 weeks, and the descending thoracic aortas were excised for pressure-diameter tests and histological evaluation to examine the relationship between aortic elastic properties and atherosclerotic lesions.
All rabbits fed the high-cholesterol diet developed either intermediate or advanced atherosclerotic lesions, particularly American Heart Association-type III and IV, which were fatty and contained abundant lipid-filled foam cells (RAM 11-positive cells) and fewer SMCs with solid-like actin staining (HHF-35-positive cells). In contrast, rabbits fed a normal diet had no visible atherosclerotic changes. The atherosclerotic lesions correlated with a statistically significant decrease in mean vessel wall stiffness in the cholesterol-fed rabbits (51.52 ± 8.76 kPa) compared to the control animals (68.98 ± 11.98 kPa), especially in rabbits with more progressive disease.
Notably, stiffness appears to decrease with the progression of atherosclerosis after the 8-week period.