Studies of intense granulocytic stimulation on the hemopoietic microenvironment of the bone marrow

In an earlier study, we described the sustained suppression of both hemopoietic and stromal cell recovery in the irradiated field following large doses of partial-body x irradiation to mice. Surprisingly, we also noted long term changes in the marrow and spleen shielded from the irradiation. Our interest in these abscopal responses led us to clarify these effects. In Part I of this study, one hind leg of CF-1 female mice received 1000, 5000, or 10,000 rad of x irradiation. Studies were initiated in Part II to determine the effect of a variety of erythropoietic and granulocytopoietic stimuli on blood production and the stromal cells of the hemopoietic microenvironment. From these studies it was concluded that: (1) high doses of x irradiation to one leg of mice caused prolonged suppression of medullary erythropoiesis with splenic compensation to prevent anemia, (2) splennectomy, anemia, and hypoxia prevented the severe abscopal depression of medullary erythropoiesis, (3) transfusion or bleeding appropriately decreased or enhanced medullary and splenic erythropoiesis with no change in the growth of MSC, (4) endotoxin or turpentine caused granulocytic hyperplasia, anemia, and an inappropriately reduced erythroid response by the marrow, (5) the associated medullary erythroblastopenia in the presence of splenic erythroid hyperplasia and the suppressed growth of marrow stromal colonies suggested that intense granulocytopoietic stimulation caused a change in the marrow's hemopoietic microenvironment