Rat liver preservation by hypothermic oscillating liver perfusion compared to simple cold storage.

Rat livers were preserved hypothermically for 10 or 24 h in vitro as if for transplantation. Two methods of preservation were compared using physiological and biochemical parameters: simple storage and oscillating perfusion. By measuring the nucleotides after preservation the calculated energy charge was significantly higher after 10 and 24 h of oscillating perfusion compared to the simple storage group. In addition, a significant energy charge loading was demonstrated by 10 h oscillating perfusion compared to the initial value prior to perfusion. The oscillating, computer-controlled perfusion permits continuous monitoring of perfusate temperature, O2 consumption, pCO2, portal vein pressure, and pH and also automatic sample collection and pH compensation. In addition, the perfusate can be easily exchanged by using two different pumps or be rewarmed by a heat exchanger. For measuring of short-lived metabolites (interleukins, oxygen radicals, prostaglandins) sampling can be performed directly out of the vena cava outflow. pH and temperature stability was maintained by a data acquisition and controlling system. Because of a special designed liver chamber a combination of storage and perfusion with or without substrates was possible. The demonstrated standardized perfusion technique was achieved by a combination of special equipment and computer-aided monitoring and allows further experiments to improve understanding of ischemic and reperfusion injury.