Role of sodium nitroprusside in the improvement of rat liver preservation in University of Wisconsin solution: A study in the isolated perfused liver model

Background. Long-term liver preservation is needed to transform liver transplantation from an emergency operation into an elective procedure and, therefore, to improve the results of liver transplantation. Aims. We have studied the possibility of extending the period of cold ischemia of the rat liver, maintaining good hemodynamics and functional conditions, by adding the NO donor sodium nitroprusside (NPNa) to the preservation solution. Materials and Methods. Rat livers were preserved for 24, 48, and 72 h in University of Wisconsin solution (UW) at 4 degrees C (groups I, II, and III) or UW to which 500 mu M NPNa was added (groups TV, V, and VI). Following the preservation time, liver viability was assessed using the isolated perfused liver model. Lactate dehydrogenase (LDH) and K+ release, bile flow, and portal resistance were evaluated in each group and compared with those of liver controls (group VII) excised and perfused without preservation. Results. Some deleterious effects can be seen during cold storage conditions as assessed by an increment in intrahepatic resistance and a diminution in the capacity of the organ. to produce bile. On histological observation, we see vacuolated hepatocytes and free endothelial cells (detached) in the sinusoidal lumen. Addition of 500 mu M NPNa to UW significantly moderates these injuries, with an improvement in intrahepatic circulation (less intrahepatic resistance), an increment in bile production, and better histological appearance of the organ. We were also able to determine the capacity of the UW + NPNa to produce NO. Conclusion. We assume that the beneficial vascular effects of NPNa are mediated by NO production. (C) 1999 Academic Press.