The effect of E. coli endotoxin on the developing rat liver. II. Immunohistochemical localization of alpha-fetoprotein in rat liver multinucleated giant cells

Abstract

Immunoperoxidase histochemical staining techniques have been used previously to localize alpha-fetoprotein (AFP) in hepatocytes from rat and human liver tissues. In this study, we extended these observations by examining liver tissues from rat fetuses exposed to E. coli endotoxin in order to document the presence of AFP in hepatic multinucleated giant cells. Liver sections were examined under light microscopy after incubation with purified antibody-peroxidase conjugates and histochemical stains. These sections showed a positive reaction for AFP in giant cells and hepatocytes that appeared as granular, brown intracytoplasmic deposits in cells throughout the hepatic lobule. Furthermore, a direct correlation was found between the number of positively stained giant cells and the serum concentration of AFP. The findings demonstrated that AFP distribution in endotoxin-induced liver injury is confined to isolated hepatocytes and multinucleated giant cells. This observation provides evidence that the origin of the giant cell in toxin-exposed fetal rat liver may be the hepatocyte.