RESPONSE OF IMMOBILIZED HEPATOCYTES IN A PERFUSION SYSTEM TO ANOXIA REOXYGENATION - EFFECT OF CYCLOSPORINE-A PRETREATMENT/

The present study was designed to investigate the ameliorative effect of cyclosporine A (CsA) pretreatment on an anoxia/reoxygenation injury model by using immobilized perfused hepatocytes. Rats received an i.p . injection of two successive doses of CsA (5 mg/kg/day). Twenty-four hours later hepatocytes were isolated from CsA-treated and control rat s. After hepatocyte isolation, immobilization, perfusion, induction of anoxia/reoxygenation, the structural and functional integrity of the hepatocytes was followed in a perfusion medium by measuring the leakag e of lactate dehydrogenase (LD) and the time course of urea biosynthes is. CsA pretreatment reduced the initial rate of urea synthesis during normoxia but reduced the drop in the relative percentage rate of urea synthesis during the period of anoxia. LD leakage was increased three fold by anoxia and sevenfold by reoxygenation in cells of untreated an imals. After CsA pretreatment in vivo, hepatocytes showed no increase in LD leakage into the medium. These findings demonstrate that the per fused immobilized hepatocytes can be used as a cellular model to asses s the effects of liver insults such as anoxia/reoxygenation injury and that CsA modulates the injury. The mechanisms of CsA beneficial effec ts at the experimental level remain to be elucidated.