HEPATIC FREE-RADICAL PRODUCTION AFTER COLD-STORAGE - KUPFFER CELL-DEPENDENT AND CELL-INDEPENDENT MECHANISMS IN RATS

Background/Aims: Free radicals are important mediators of reperfusion injury; however, the mechanism(s) of oxyradical production after liver reimplantation ave not well understood. A model of cold storage and r eperfusion using low-level chemiluminescence to directly measure oxyra dical production during reperfusion was developed. Methods: Rat livers were harvested and stored at 4 degrees C in University of Wisconsin c old-storage solution or Euro-Collins solution for 0-48 hours and then flushed and reperfused with warm oxygenated (37 degrees C) Krebs-Hense leit buffer. Liver chemiluminescence was measured using a sensitive ph otomultiplier tube, and hepatocellular injury was assessed by measurin g aspartate aminotransferase release into the perfusate. Results: Chem iluminescence reached a maximum within 5 minutes of reperfusion and th en decreased to a baseline within 30 minutes. There was a marked incre ase in chemiluminescence after only a short period of storage in Unive rsity of Wisconsin cold-storage solution. Chemiluminescence decreased with longer periods of storage but steadily increased again after 16 h ours of storage. Chemiluminescence after 22 hours of storage, but not after 3 hours of storage, was decreased by pretreatment with the Kupff er cell inactivator gadolinium chloride. Conclusions: The data suggest two mechanisms of oxyradical production during cold storage and reper fusion of the rat liver. The later phase seems to be Kupffer cell depe ndent.