Abscopal Suppression of Bone Marrow Erythropoiesis

Abstract

WERTS, E. D., JOHNSON, M. J., AND DEGOWIN, R. L., Abscopal Suppression of Bone Marrow Erythropoiesis, Radiat. Res. 76, 206-218 (1978). Abscopal responses of hemopoietic tissue, which we noted in preliminary studies of mice receiving partial-body X irradiation, led us to clarify these effects. In studies reported here, one hind leg of CF-1 female mice received 1000, 5000, or 10,000 rad of X radiation. We found a persistent shift from medullary to splenic erythropoiesis preventing anemia in mice receiving 5000 or 10,000 rad. Splenectomy prior to 5000-rad irradiation resulted in anemia, which was not ameliorated by exposure to intermittent hypoxia. Despite evidence for increased levels of erythropoietin in the animals, namely, a reticulocytosis and increased erythrocyte radioiron incorporation, both 69Fe uptake and erythroblast counts in shielded marrow remained below normal. We found 50 to 90% suppression of the growth of marrow stromal colonies (MSC) from bone marrow aspirates of the shielded and irradiated femoral marrow at 1 month and at least 20% depression of MSC at 1 year, with each dose. We conclude that (i) high doses of X radiation to one leg of mice caused prolonged suppression of medullary erythropoiesis with splenic compensation to prevent anemia, (ii) splenectomy, anemia, and hypoxia prevented the severe abscopal depression of medullary erythropoiesis, and (iii) suppressed medullary erythropoiesis with decreased growth of MSC suggested a change in the hemopoietic microenvironment of the bone marrow.