IMPAIRMENT OF GRAFTS BY SHORT-TERM WARM ISCHEMIA IN RAT-LIVER TRANSPLANTATION

The mechanism of warm ischemic damage was investigated by assessing hepatic energy metabolism, mitochondrial functions, and lipid peroxidation (LP) of transplanted liver grafts in rats. Donor livers were stored ischemically either for 90 min at 4-degrees-C (control) or for 20 min at 37-degrees-C and 70 min at 4-degrees-C (warm ischemia). In the control group, adenosine 5'-triphosphate (ATP) recovered within 8 min to 86% of the normal preischemic value (10.30, SEM 0.26-mu-mol/g dw). Total adenine nucleotides (TAN) recovered to 14.83 (SEM 0.22) mu-mol/g dw within 30 min, as compared with a normal level of 15.44 (SEM 0.36) mu-mol/g dw. The energy charge potential (ECP) immediately recovered to 0.79 (SEM 0.01) within 8 min (normal, 0.81, SEM 0.01). Mitochondrial phosphorylation rate (PR) was not significantly altered. LP averaged 451 (SEM 10) nmol/g dw in normal livers and did not change even during reperfusion (504, SEM 79, nmol/g dw, at 15 min). In contrast, in the warm ischemic group, ATP recovered only to 65% of the normal value even at 30 min (P < 0.01), and TAN remained significantly lower than the control value (12.39, SEM 0.47, mu-mol/g dw, P < 0.001). PR was normal at the end of warm ischemia, was significantly reduced at the end of the total ischemic period (P < 0.001 and P < 0.01, as compared with control and normal values, respectively), and gradually recovered over 30 min. LP increased and reached the maximum of 795 (SEM 84) nmol/g dw at 15-min reperfusion (P < 0.05). In grafts treated with 50 mg/kg bw allopurinol (i.v.) 10 min prior to the onset of warm ischemia, ATP and ECP recovered to normal values at 30 min, and TAN was significantly higher than in the warm ischemic group (13.28, SEM 0.28, mu-mol/g dw, P < 0.05). PR was maintained at normal values, and LP was increased but to a lesser degree than in the ischemic group. It is concluded that the delayed recovery of ATP metabolism in the warm ischemic group might be due to the loss of adenine nucleotides and the decreased PR, and that allopurinol has a protective effect against warm ischemic damage.