Effects of temperature and preservation time on the pharmacological response of isolated vascular endothelial and smooth muscle function.

In clinical transplantation and cardiovascular surgery, cold preservation is usually used because it is a simple method. However, the established temperature is by no means exact. The aim of this study was to find the optimum storage temperature for preservation of the vasculature by observing the pharmacological endothelium and smooth muscle response. The thoracic aorta of 36 male Wister rats were studied in organ baths: as fresh control after 24 hours, 48 hours and 72 hours of storage at 0.5 degree C, 4 degrees C and 8 degrees C in Krebs-Henseleit bicarbonate (KHB) solution. Acetylcholine (Ach) was used to elicit endothelium-dependent relaxation, and sodium nitroprusside (SNP) to elicit smooth muscle-dependent relaxation. The contractility caused by Phenylephrine (Ph) was influenced by time but before 48 hours it was not influenced by preservation temperature. Significant responsive deterioration by Ach and SNP was seen after 24 hours of storage at 0.5 degree C as compared with storage at 4 degrees C. The endothelium-dependent relaxing function and smooth muscle-dependent relaxing function were best preserved at 4 degrees C and 8 degrees C. These results indicate that precise temperature control is necessary for vessel preservation in clinical situations.