39. Strain Differences in Carcinogenic and Hemopoietic Responses of Mice Following Injection of Plutonium Citrate
Yoichi Oghiso and Yutaka Yamada
Keywords: osteosarcoma, lymphoma, hematology mouse strains, 239Pu citrate
The carcinogenicity of injected 239Pu citrate was compared among C3H, C57BL/6 and BC3F1 hybrid strains of female mice with different spontaneous or radiation-induced tumor spectra. Significant survival reduction due to early neoplastic death particularly caused by induction of osteosarcomas was noted in each strain after injection of 500 Bq or more. The dose response of osteosarcomas appeared to show mostly similar patterns in each strain, ex cept for the differences in the skeletal dose ranges for the maximum induction. While the incidence of lymphoid tumors decreased as osteosarcomas sharply increased up to the maximum at higher doses, their histological phenotypes were predomt nantly non-thymic, pre-B-cell leukemia lymphomas as compared to the controls in each strain. Myeloid leukemias were rarely or not observed and solid tumors involving other organs were rather reduced in each strain after injection of 500 Bq or more.
To follow up the hematological kinetics related to alpha particle irradiation of bone marrow hemopoietic stem cells, sequential examunatnons were done in each strain of mice within one year after injection of 5000 Bq. The cellularities of peripheral white blood cells and bone marrow cells were persistently reduced in each strain from the early periods, while spleen cells increased from 180 days later. Granulocyte-macrophage and macrophage colony-forming cells (GMand M-CFC) were also persistently reduced in the bone marrow, but were compensatively increased in the spleen from the early periods. Neither myeloid nor lymphoid tumors were found in any strains of mice during one year after the injection.
These findings indicate carcinogenic and hemopouetuc responses specific to alpha particle irradiation, but independent of mouse strains injected with 239Pu citrate.
Publications:
Oghiso,Y.and Yamada,Y.: Radiat.Res., 153, S27 S30 1999.