Effect of Elastase on the Elastic Tissues in the Thoracic Aorta

Abstract

Since elastase participates not only in elastolysis but also in elastogenesis, it has been regarded as a regulator of elastin metabolism. According to Balo and Banga, the enzyme decreases with the aging of animals and in patients with arteriosclerosis. In this study, the effect of elastase on the elastic tissues of the thoracic aortas of young and old rats was examined using morphological and histochemical techniques. From the findings obtained, the elastic laminae and elastic branches in the thoracic aortas excised from elastase-administered rats did not look parched in contrast to those of control rats. The resistance of the elastic tissues for elastase digestion in vitro increased with aging of the animals. However, the elastic tissue in the thoracic aortas of the old rats administered with elastase became susceptible to elastase digestion in vitro. In addition, the glycogen granules and contours of the smooth muscle cells became compatible with those of young controls.
Thus, from the morphological standpoint, elastase appears to play an important role in maintaining the physiological architecture of the vascular wall of the thoracic aorta.