Kupffer cells depress hepatocyte protein synthesis on cold storage of the rat liver

Abstract

The causes of liver failure after transplantation are multifactorial. An understanding of the mechanisms of injury to the liver could help to define methods to improve preservation and transplantation. We measured protein synthesis by 3H-leucine incorporation into acid precipitable protein in rat liver tissue slices, isolated hepatocytes, and isolated perfused liver (IPL) after cold storage for 24 or 48 hr in University of Wisconsin (UW) solution. Some rats were pretreated with dexamethasone prior to liver harvest. Protein synthesis was depressed in all in vitro models after 24 hr storage. The percent decrease was greater in tissue slices and IPL (about 70% decrease relative to fresh livers) than in isolated hepatocytes (about 30% decrease). Dexamethasone pretreatment improved protein synthesis significantly after 24 hr preservation in tissue slices and in IPL, but had no significant effect on protein synthesis in isolated hepatocytes. The greater loss of protein synthesis in tissue slices and IPL compared with that in isolated hepatocytes was considered in relation to the presence of Kupffer cells in the former systems and lack of Kupffer cells in the isolated cell suspensions. Kupffer cells generate cytotoxins that could cause injury to metabolically depressed hepatocytes or endothelial cells. Dexamethasone has been shown to modulate Kupffer cell inhibition of hepatocyte functions. The results suggest that preservation damage to hepatocytes sensitizes them to further damage on reperfusion by Kupffer cell-generated agents.