[Remodeling and biomechanical properties of thoracic aorta in spontaneously hypertensive rats]

Morphometry and microstructure of thoracic aorta of spontaneously hypertensive rats (SHR) at different periods before and after hypertension were studied quantitatively by histological method and computer image analysis. We also observed the changes of opening angle in the zero-stress state and the relationship between pressure and diameter in SHR during established hypertension. The results showed that with blood pressure chronically increasing, there was a significant increase in morphometric parameters and microstructure parameters of the thoracic aorta in SHR. The zero-stress state of opening angle in SHR during established hypertension increased significantly. These reults suggest that aortic structural remodeling in hypertension such as thickness of vascular wall and disproportional increase of collagen may lead to decrease in distensibility of the aorta in SHR. The structural remodeling and changes of mechanical properties in aorta may contribute to the important pathophysiology of hypertension-induced complications.