Leukocyte adhesion and cell death following orthotopic liver transplantation in the rat

The purpose of these experiments was to employ video microscopy to identify early pathological changes after orthotopic liver transplantation in the rat. Liver transplantation was performed using the cuff technique. Survival was greater than 90% when livers were stored for 1 hr in Ringer's solution prior to transplantation (survival conditions), whereas all rats died following storage of grafts for 4 hr in cold Euro-Collins solution (nonsurvival conditions). Postoperatively, each recipient animal was anesthetized, the abdomen was opened, and the liver was placed on the stage of an inverted fluorescence microscope equipped with a low-light ISIT video camera. Precautions were taken to prevent the liver surface from drying. The fluorescent dyes fluorescein sodium (1.0 mumol/kg), acridine orange (2.5 mumol/kg), and propidium iodide (1 mumol/kg) were injected intravenously to label hepatocytes, polymorphonuclear leukocytes, and the nuclei of irreversibly damaged cells, respectively. In livers from untransplanted rats, movement of labeled leukocytes through the hepatic sinusoids was smooth and rapid (velocity, 500-550 microns/sec) and margination (adhesion) of cells was minimal (less than 1%). After transplantation, however, velocity was diminished 2-3-fold, and margination was increased to 10% of leukocytes in survival groups and to 40% in nonsurvival groups 4 hr postoperatively. In the nonsurvival groups, irreversible cell death detected by propidium iodide fluorescence was minimal 15 min after transplantation--however, massive cell damage was detected 4 hr postoperatively. In addition, serum transaminases and necrosis were higher at 4 hr than 15 min postoperatively. Taken together, these data demonstrate that leukocyte margination increases following orthotopic liver transplantation and is followed rapidly by cell death. These events likely play a role in the mechanism of early graft failure following transplantation.