Cytophotometric Deoxyribonucleic Acid Studies on Livers of Xenogeneic Radiation Chimeras

Abstract

HEPATOMEGALY has been described as an early manifestation of bone marrow injection into lethally irradiated or normal mice. Congdon and Kretchmar¹ reported that liver weight returned to normal in syngeneic chimeras by three weeks post-treatment, but that hepatomegaly continued in allogeneic chimeras throughout a 95-day post-treatment period. (The terms used here describe chimeras resulting from the injection of donor cells from the same strain (syngeneic), different strain (allogeneic) and different species (xenogeneic) to X-irradiated hosts.) Little information exists concerning the early phase of this tissue reaction. The nuclear DNA content of liver parenchymal cells of xenogeneic radiation chimeras during the first two weeks after treatment with rat bone marrow or spleen cells was therefore examined. Since it has been suggested¹ that the enlarged liver is due to individually enlarged parenchymal cells, it was of interest to determine whether there was a shift of the parenchymal cell population to one of higher DNA content.