Ultrastructural changes in hepatocytes, sinusoidal endothelial cells and macrophages in hypothermic preservation of the rat liver with University of Wisconsin solution.

To identify subtle changes which might lead to liver failure after liver transplantation, rat livers stored at 4 degrees C in University of Wisconsin solution for 8, 16, 24, and 32 h were examined by transmission electron microscopy, scanning electron microscopy, cellular matrix maceration and freeze fracture for ultrastructural analysis. Endothelial cells exhibited aggregation of intramembrane particles (IMPs) at 8 h and produced tiny blebs accompanied by marked development of pits. As deterioration advanced, endothelial cells exposed the perisinusoidal faces of hepatocytes directly to the lumen with destruction of sieve plates. They then degraded with loss of IMPs. Macrophages followed a similar deterioration process to endothelial cells. Membranes of hepatocytes did not demonstrate aggregations of IMPs for 32 h. Rough endoplasmic reticulum (rER) lost ribosomes and smooth ER (sER) increased in amount and dilated in an irregular form. Autophagosomes appeared in the cytoplasm, engulfed cytoplasmic matrix containing intracellular organelles and became autophagic vacuoles. At 32 h bile canaliculi were filled with detached vesicles. This may be one of the causes of preservation related bile duct complications after liver transplantation.