Corrugated intimal surface of normal thoracic aorta in sheep

Abstract

The aortic lumen in healthy animals is characterized by a smooth, whitish surface, but sheep show macroscopic corrugation of the intimal surface in the thoracic aorta (TA). Our aim was to determine if this finding was pathological or physiological. Thirteen sheep aortas were included in this work together with aortas from bovines (n=3), goats (n=1), horses (n=4), dogs (n=2), rabbits (n=2), and pigs (n=1). In all sheep, a corrugated intimal surface in the TA was observed. Similar findings were seen in the goat and were less evident in cattle. Histologically, in sheep, the TA intimal surface showed multifocal bulging areas that protruded into the lumen. The outer half of the tunica media showed numerous, randomly distributed muscle islands, that disrupted the arrangement of the elastic lamella, displacing these elements towards the lumen. The intimal corrugation of the TA in sheep is physiologic and must not be misinterpreted with pathology.