Protection of the rat liver against rewarming ischemic injury by University of Wisconsin solution

Background/aim: University of Wisconsin (UW) solution has been proven able to prevent liver injury during cold ischemia. During rewarming ischemia, ho wever, the efficacy of this solution in preserving hepatocyte function is u nclear. The aim of the present study was to investigate to what extent UW s olution protects rat liver during rewarming ischemia. Methods: Livers were washed out with cool physiologic saline or with UW solution and subjected t o rewarming ischemia for periods of 20 min or 45 min followed by reperfusio n using a blood-free perfusion model. Results: In comparison with controls, ischemia for 20 min in saline-treated livers led to mild depression of hep atocyte function, while UW solution afforded complete protection of the liv er. In UW-treated livers, compared with saline-treated livers exposed to is chemia for 45 min, portal flow was slightly but significantly higher, bile production was increased by 62%, and lactate dehydrogenase leakage into the perfusate was reduced by 61%. In an attempt to explain mechanisms of liver protection by UW solution, we found that UW solution inhibited conversion of hypoxanthine into uric acid, but this effect was not associated with dec reased degradation of adenine nucleotides in the liver during ischemia. Fol lowing 30 min reperfusion, UW solution increased tissue levels of adenosine triphosphate (not significantly) and adenosine diphosphate (significantly) . Further, UW solution markedly reduced tumor necrosis factor-alpha release by the liver both after ischemia and after reperfusion. Conclusions: These results create the hypothesis that UW solution may protect liver tissue du ring ischemia in liver surgery as well as during the implantation stage of liver transplantation.