A Morphometric Study of the Structural Characteristics of the Aorta in Pigs Using an Image Analysis Method

The objective of this study was to evaluate multiple structural characteristics, in addition to vasa vasorum density, in different aortic regions. The aorta of healthy Landrace pigs was divided into four thoracic and three abdominal segments. Transverse sections were reserved for morphometric analysis. Image analysis showed the aortic diameter, the thickness of the media, the number of elastic lamellae and the thickness of elastic membranes being reduced with increased distance from the heart (P < 0.05). The average thickness of lamellar units remained constant in the thoracic, but increased in the abdominal aorta (P < 0.05). The number of lamellar units, contained in the avascular zone of the media, and the density of vasa vasorum decreased peripherally (P < 0.05), still the average thickness of the avascular zone was invariant. In conclusion, the anatomical properties of the vessel wall alter through the aorta, being optimal for the varying stresses to which the aorta is subjected along its length. The distinct aortic parts may exhibit inherent morphological features, responsible for the various pathological processes that affect the aorta.