Comparison of experimental hypercholesterolemia and atherosclerosis in Göttingen mini-pigs and Swedish domestic swine.

Mini-pigs of the Göttingen strain and domestic swine of the Swedish Landrace were compared with respect to their susceptibility to alimentary hypercholesterolemia and experimental atherosclerosis. Hypercholesterolemia was produced in both strains by adding 11.2% egg yolk and 0.5% cholesterol to the diet. The plasma cholesterol rose significantly faster and reached a higher level in the mini-pigs than in the domestic swine. In both strains most of the elevated plasma cholesterol was found in the low density lipoprotein fraction. The basal plasma triglyceride level was higher in the mini-pigs and increased transiently in this strain when the lipid-rich diet was given. After 18 months of hypercholesterolemia all animals were killed and the aorta and the coronary arteries were examined for atherosclerotic lesions. The arterial content of free and esterified cholesterol, triglycerides and phospholipids were determined. From colour photographs of the aorta the percentage area of visible atherosclerosis in the abdominal part was calculated. Coronary arteries from both strains were sectioned and stained for microscopic investigation. Atherosclerotic lesions were found in the abdominal aorta in both strains and in the coronary arteries in the mini-pigs. In the coronary arteries from domestic swine no macroscopically visible atherosclerosis was found and the content of all arterial lipids was lower than in the mini-pigs. Microscopically, the coronary arteries from the mini-pigs showed pronounced intimal proliferative atheromatous lesions, whereas no atheromas were observed in the domestic swine. In the thoracic and abdominal aorta, however, there were no differences between the two strains, either with regard to the cholesterol and phospholipid content or in the atherosclerotic area. The content of triglycerides was somewhat higher in the abdominal aorta from mini-pigs than in that from domestic swine.