Protective effect of prostaglandin I2 on hepatic mitochondrial function of the preserved rat liver.

Mitochondrial function of the liver is one of the limiting factors in liver preservation. Nowadays, prostaglandin I2 (PGI2) is used as a cytoprotective agent in liver preservation without full understanding its mechanism involved. It is the objective of the present study to evaluate the protective effect of PGI2 on mitochondrial function of the rat liver during hypothermic preservation. Collins' solution was used as a preservation solution and PGI2 was added to it in some experimental groups. Both ischemic and non-ischemic livers were perfused with the preservation solution and preserved under simple hypothermia for 8 hr. Parameters of the mitochondrial function such as respiratory control, oxygen consumption rate in state 3 respiration, ADP/O ratio and the rate of ATP synthesis were decreased significantly after 8 hr hypothermic preservation, even if ischemic injury was not induced prior to preservation. ADP/O ratio, which represents the efficiency of oxidative phosphorylation in mitochondria, was improved significantly (p less than 0.01) when PGI2 was used as a cytoprotective agent. The rate of ATP synthesis, a parameter of energy producing reaction, showed a tendency to be increased by PGI2, but was not significant. It was concluded that hypothermic preservation of the rat liver is associated with the deterioration of the mitochondrial function and PGI2 has a favorable effect on the impaired ADP/O ratio of oxidative phosphorylation in mitochondria.