An improved system for hemoglobin-free perfusion of isolated rat livers.

Fine structure and several parameters of hepatic function were evaluated in isolated rat livers perfused with a hemoglobin-free medium in a newly designed organ perfusion system. The preservation of hepatic fine structure and the maintenance of certain functional criteria, including oxygen consumption, bile secretion rate, and the retention of intracellular potassium ions, demonstrated that these livers had been successfully perfused for up to 5 hours. The medium contained neither red blood cells nor other oxygen carriers, such as fluorocarbon emulsions. The use of hyperbaric oxygenation eliminates the requirement for hemoglobin in the perfusion medium. In addition, the extensive endothelial cell injury associated with the use of hemoglobin-free media is avoided since this system permits perfusion at near physiologic hepatic portal vein flow rates. The quality of isolated livers perfused without albumin in medium suggests that an oncotic agent is not required for rat liver perfusion.