Heat shock protein 70 messenger RNA reflects the severity of ischemia/hypoxia-reperfusion injury in the perfused rat liver

Objectives: To determine whether ischemia-reperfusion and hypoxia-reoxygenation cause cellular damages and stress responses in an isolated perfused rat liver model. To determine whether the increased synthesis of stress protein messenger RNA reflects cellular injury. Design: Prospective, controlled study. Setting: Institutional laboratories. Subjects: Male Sprague-Dawley rats. Interventions: Isolated rat livers with cell free perfusion were exposed to various periods of ischemia-reperfusion or hypoxia-reoxygenation. Measurements and Main Results: We measured hepatic oxygen consumption and alanine aminotransferase leakage from liver during perfusion. We analyzed the gene expression of heat shock protein 70, a major stress protein, of the liver by Northern blotting after perfusion. The expression of heat shock protein 70 messenger RNA augmented as the reperfusion period increased. The expression level after graded ischemia or hypoxia significantly correlated with the calculated hepatic oxygen debt (r(2) =.737; p < .001; n = 21), or with the accumulated alanine aminotransferase leakage from the liver (r(2) =.509; p <.001; n = 21). Conclusions: These results suggest that the accumulation of heat shock protein 70 messenger RNA reflects the severity of ischemia-reperfusion and hypoxia-reoxygenation injuries, and that a stress response in reperfusion can be triggered without formed elements of blood.