Atherosclerosis in Watanabe heritable hyperlipidaemic rabbits. Evaluation by macroscopic, microscopic and biochemical methods and comparison of atherosclerosis variables.

The spontaneous development of atherosclerotic disease in 38 homozygous and 34 heterozygous Watanabe heritable hyperlipidaemic rabbits was evaluated by qualitative and quantitative light microscopy in aorta, coronary, pulmonary and renal arteries, by naked eye and macroscopic morphometric estimation of aortic atherosclerosis extent and by biochemical analysis of aortic cholesterol content. No noteworthy atherosclerosis was demonstrated within 19 months in heterozygous rabbits. In homozygous rabbits, atherosclerotic lesions were seen from the age of 4 months and progressed with age. All 19-month-old rabbits had severe atherosclerotic disease. As much as 64% of the variation in atherosclerosis extent/severity could be explained by serum cholesterol and age. A highly significant correlation between the various methods for quantitation of atherosclerosis extent and/or severity was demonstrated, suggesting that quantitative microscopy, macroscopic morphometry and determination of aortic cholesterol content may be equally valid as a measure of atherosclerosis in WHHL rabbits and are therefore interchangeable.