Vascular Compliance and Vasoconstrictive Reactions in Rat Hindlimbs: Comparison Between Storage Temperatures of -1°C and 4°C

ABSTRACT

The vascular compliance and contractility of vascular smooth muscle of rat freshly amputated hindlimbs and hindlimbs preserved at -1°C for 12, 24, 48, and 72 hr were evaluated using a fresh blood extracorporeal circulatory system. Vascular compliance was measured under physiologic circulatory conditions (blood pressure of the amputated limb was maintained at 80 to 150 mmHg). Vascular compliance after storage at -1°C for 12 hr or longer decreased significantly from that of freshly amputated limbs (p < 0.01). To evaluate the contractility of vascular smooth muscle, the arterial blood pressure in the amputated limbs was transiently increased with injections of norepinephrine. The contractility after storage at -1°C for up to 24 hr was not different from that of freshly amputated limbs. However, it decreased significantly after 48 hr or longer. A comparison of these results with an earlier study that used identical methods to investigate limbs preserved at 4°C suggested that storage at -1°C was inferior to that at 4°C with respect to vascular compliance, but was superior to storage at 4°C with respect to smooth muscle contractility.