Effect of temperature increase on the distensibility of porcine thoracic aorta.

The objective of the study was to investigate the temperature impact on the elasticity of porcine thoracic aorta. Under general anesthesia, 16 Landrace pigs were subjected to thoracotomy, and the descending thoracic aorta was removed and stored in normal saline. Serial sections of the vessel created cylindrical aortic specimens which were tested in a uniaxial tension device to determine the elastic properties of the aortic wall. In the control, Group A (n = 8), the aortic tissues were tested while immersed in normal saline bath of temperature TA = 37.0 +/- 0.5 degrees C, while in Group B, the temperature was TB = 40.0 +/- 0.5 degrees C. Each experiment took place only after the tissues had remained for 15 min in temperature TA or TB. For the results, the stiffness modulus of Group B showed a significant decrease (P < 0.05) at medium strain level deformation (e = 1, SB1 = 114 +/- 8 Pa) as well as at high strain level deformation (e = 2, SB1 = 1182 +/- 48 Pa) in comparison with the control, Group A (e = 1, SA1 = 147 +/- 15 Pa; e = 2, SA1 = 1479 +/- 64 Pa). It is concluded that temperature increase facilitates, in vitro, the expansion of descending thoracic aorta. We assume that thermal treatment may be another means against the stiffening of aorta, which calls for further research.