Fate of 51Cr labeled lipopolysaccharide in tissue culture cells and livers of normal mice

Abstract

Livers of normal mice trapped over 80% of intravenously injected 51Cr labelled lipopolysaccharide after 1 hr. Liver fractionation studies showed that nearly 45% of the labeled endotoxin was associated with cell nuclei, 20% with the mitochondrial lysosomal fraction, and approximately 30% with the cell sap. Analysis of the distribution of 51Cr labeled lipopolysaccharide among parenchymal and Kupffer cells showed that over 75% of the in vivo trapped counts were parenchymal cell associated. Cell populations were approximately 65% parenchymal cells and 35% nonparenchymal cells. Further, 6 non reticuloendothelial system tissue culture cell lines were tested for their ability to internalize labeled lipopolysaccharide. In all cells studied, 1 to 4% of the labeled lipopolysaccharide was taken up after 3 hr, with greater than 80% of the counts localized in the nuclear fraction. The data show that non reticuloendothelial system cells can sequester endotoxin both in vivo and in vitro and suggest that parenchymal cells as well as Kupffer cells remove circulating endotoxin from the blood.