Background/aims: Free radicals are important mediators of reperfusion injury; however, the mechanism(s) of oxyradical production after liver reimplantation are not well understood. A model of cold storage and reperfusion using low-level chemiluminescence to directly measure oxyradical production during reperfusion was developed.
Methods: Rat livers were harvested and stored at 4 degrees C in University of Wisconsin cold-storage solution or Euro-Collins solution for 0-48 hours and then flushed and reperfused with warm oxygenated (37 degrees C) Krebs-Henseleit buffer. Liver chemiluminescence was measured using a sensitive photomultiplier tube, and hepatocellular injury was assessed by measuring aspartate aminotransferase release into the perfusate.
Results: Chemiluminescence reached a maximum within 5 minutes of reperfusion and then decreased to a baseline within 30 minutes. There was a marked increase in chemiluminescence after only a short period of storage in University of Wisconsin cold-storage solution. Chemiluminescence decreased with longer periods of storage but steadily increased again after 16 hours of storage. Chemiluminescence after 22 hours of storage, but not after 3 hours of storage, was decreased by pretreatment with the Kupffer cell inactivator gadolinium chloride.
Conclusions: The data suggest two mechanisms of oxyradical production during cold storage and reperfusion of the rat liver. The later phase seems to be Kupffer cell dependent.