Deacylation of bacterial lipopolysaccharide in rat hepatocytes in vitro

The possible role of liver parenchymal cells in the uptake and degradation of bacterial lipopolysaccharide (LPS) was investigated in vitro by employing radiolabelled LPS as substrate. Hepatocytes obtained from Wistar rats by collagenase treatment were found to take up LPS only when it was not linked to the polysaccharide of O-antigen. The amount of LPS taken up increased with time and after 48 h incubation it increased in a dose-dependent manner up to at least 30 micrograms. When incubated with LPS radiolabelled exclusively in the fatty-acid moiety, cultured hepatocytes released lipophilic materials into the culture medium. These were identified as beta-hydroxytetradecanoic acid and triglyceride, in the ratio of 7:I. These results indicate that the R-form of LPS which lacks the O-antigen polysaccharide is taken up and deacylated in hepatocytes, and the derived fatty acids are released into the culture medium either in the free form or after conversion to triglyceride.