Time-related morphological changes in cold-stored rat livers. A comparison of Euro-Collins solution with UW solution

Rat livers were stored in cold UW solution and Euro-Collins solution for various periods. Morphological investigations were performed using light microscopy, as well as scanning and transmission electron microscopy. In the UW-stored livers, the appearance of blebs derived from hepatocytes and the destruction of sinusoidal endothelial cells (SEC) occurred more slowly than in the EC-stored livers. Almost no ultrastructural damage in the hepatocytes was observed even after 48 hr of storage in UW solution, while extremely swollen and degenerated hepatocytes were observed in the 48-hr EC-stored livers. After 48-hr of storage, livers stored in UW solution lost 7.9% of their weight though EC-stored livers gained 29.7% of weight. Light microscopic morphometry revealed that there was a significant increase of 24.3% in the mean hepatocyte area of 24-hr EC-stored livers, whereas the UW-stored hepatocytes did not show any significant increase even after 48 hr of storage. After perfusion fixation, livers stored for more than 8 hr in EC solution showed a mosaic pattern of uneven fixation indicating a microcirculatory disturbance, whereas the UW-stored livers showed a rather uniform fixation after 12 hr of storage. It is suggested that the microcirculatory disturbance occurred more slowly in the UW-stored livers than in the EC-stored livers, which might be due to the protection of SEC and the suppression of bleb formation and the swelling of hepatocytes by UW solution.