Effects of removal of the adventitia of the descending aorta and structural alterations in the tunica media in pigs.

OBJECTIVE: To investigate the effects of removal of the adventitia on the tunica media in a pig model. METHODS: The experiment was performed in eight pigs. The adventitia of the descending aorta was removed. Following euthanasia, at two, four, six and eight weeks, the aortic segment was removed. Next, slices of the aorta were stained with hematoxylin and eosin (HE) and Weigert-Van Gieson. RESULTS: After two weeks there was a slight cellular breakdown in the outer third of the media. After four weeks structural breakdown of elastic fibers was observed in the outer two thirds of the same layer. In six weeks, several areas of necrosis and almost complete disruption of elastic fibers were identified. Finally, after eight weeks, there was fibrosis of the entire wall with disruption of the internal elastic lamina. CONCLUSION: The removal of the adventitia leads to degeneration of the media, determining loss of the normal structure of the aortic wall that is variable in its location, intensity and shape, depending on the length and duration of the ischemic insult.