Ultrastructural and functional studies of cryopreserved rat lungs for transplantation using a new hyperosmolal solution.
One of the most promising approaches for extending the period of tissue or organ preservation is to induce a state of cryopreservation. In this report, to achieve successful lung cryopreservation, we created a new hyperosmolal solution (HOS) containing 10% glycerol and 5% dimethyl sulfoxide (Me2SO). We compared the efficacy of HOS with that of Euro-Collins solution (ECS) in rat lung cryopreservation from an ultrastructural and functional point of view. Using ECS, widespread damage to the air-blood barrier was observed even in the lungs cryopreserved at -10 degrees C. At -196 degrees C, the capillary lumen was obstructed with a mesh-like formation derived from deteriorated endothelial cells. In contrast, using HOS, the cryopreserved lungs at -10 degrees C were characterized by well preserved endothelial cells and basal laminae, despite the existence of focal cytoplasmic swelling of epithelial cells. The endothelial cells and basal laminae were successfully preserved up to -196 degrees C. Considering the survival rates at day 7 after cryopreserved lung transplantation, the grafted left lungs functioned normally only when perfused by and preserved in HOS at -10 degrees C. These findings demonstrate that HOS was effective not only for endothelial cells and basal laminae up to -196 degrees C, but also lung cryopreservation at least up to -10 degrees C.