MORPHOLOGIC AND HISTOCHEMICAL ANALYSIS OF HEPATOCYTES TRANSPLANTED INTO SYNGENEIC HOSTS

Abstract

Suspensions of freshly isolated hepatocytes were prepared by collagenase perfusion of livers of adult Fischer 344 female rats. The cells were injected into the dorsal fascia of partially hepatectomized syngeneic hosts (106 cells per injection site). Brown nodules developed at the transplantation site. Histologic examination of the nodules revealed that the hepatocytes were arranged in cords and clusters surrounded by fibrovascular connective tissue. Bile ductules were also seen. Hepatocytes were positive for G-6-P. Staining for .gamma.-glutamyltranspeptidase showed that the parenchymal hepatocytes were mostly (.apprx. 95%) negative, whereas bile ductules were positive. These histochemical findings were seen in hepatocytes up to 3 mo. after transplantation and did not vary with the age of the transplants. EM examination of the transplanted nodules demonstrated that the cells maintained the characteristics of hepatocellular cytoplasmic structure. The relationship between the bile canaliculi and the stromal vessels was similar to the bile canaliculi and hepatic sinusoid polarity seen in the normal liver. Autoradiographic analysis showed that a fraction of the transplanted cells was active in DNA synthesis. This system may become a tool in the study of survival and neoplastic transformation of hepatocytes as a result of exposure to X-irradiation and chemical carcinogens.