Hypercholesterolemia and aortic collagen synthesis in rabbit aortas

Male adult New Zealand rabbits were fed a 2% cholesterol diet for 30 of 60 days in order to determine the effect of hypercholesterolemia on aortic collagen synthesis. Collagen synthetic activity was estimated by measuring tissue prolyl hydroxylase activity and the amount of tissue collagen was estimated by measuring tissue hydroxyproline levels. Following 30 or 60 days of feeding there was a significant increase in both tissue and serum cholesterol indicating the onset of hypercholesterolemia. Measurement of collagen synthetic activity and tissue collagen levels demonstrated no increase over control tissues. These data therefore indicate that hypercholesterolemia is not a direct stimulus of tissue collagen synthetic activity.