ALTERATIONS IN ACID MUCOPOLYSACCHARIDE AND COLLAGEN OF RABBIT AORTA RELATED TO AGE OF EPINEPHRINE-THYROXINE INDUCED ARTERIOSCLEROTIC LESIONS

Abstract

Male albino rabbits were injected with epinephrine plus 1-thyroxine for 12 days and then sacrificed in 5 groups 3, 7, 14, 21 and 28 days after cessation of the injections. An increase in hexosamine/ hydroxyproline-ratio, uronic acid/hydroxyproline-ratio and uptake of S35-sulphate in acid mucopolysaccharides in group I 3 days after cessation of the injections was observed in contrast to a decrease in groups II to V reaching the level of untreated controls 28 days after cessation of the injections. On comparison between determinations on crude tissue and on isolated acid mucopolysaccharide, it was found, that the alterations in total hexosamine content and uptake of 35S-sulphate measured on crude tissue reflected alterations in the acid mucopolysaccharide fraction of the aortic wall. The changes were similar to those observed in granulation tissue and confirmed the previous interpretation of the epinephrine-thyroxine induced alterations as repair processes elicited by injury to the aortic wall. The gross arteriosclerotic lesions in aortae showed no cnanges from group I to V. The age of the lesions, rather than the gross lesions as sucn determined the degree of change in acid mucopolysaccharide and collagen of the arterial wall.