Red cell repopulation in irradiated mice treated with plethoric homologous bone marrow

¹ Biology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee

Marrow from normal homologous donors injected into heavily irradiated recipients results in a fast and permanent replacement of host- by homologous donor-type erythrocytes. Plethoric marrow, produced by artificial polycythemia, was capable of red cell repopulation of an irradiated homologous host. Repopulation was slower from plethoric than from normal marrow but reached 100% donor type and remained permanently at that level in all chimeras tested. There was a large decrease in hematocrit within the first 2 weeks after X-ray and bone marrow treatment in some, but not all, homologous combinations tested. In the combination studied most extensively, lethally irradiated (C₃H x 101)F₁ receiving (C₅₇L x A)F₁ marrow, the early anemia was considerably ameliorated by the use of plethoric in place of normal marrow. Possible mechanisms for these effects are discussed. It is suggested that plethoric marrow has a potential greater than that of normal marrow for producing blood platelets and can rapidly effect repair of capillary walls and thus reduce early red cell loss.