Erythropoietic response of mice to a single dose of myleran

Abstract

The response of the erythropoietic system of mice (B6D2) to a single dose of Myleran (60 mg/kg body wt.) was followed for 30 days after injection by examining a variety of bone marrow and peripheral blood parameters. In the bone marrow, determinations were made of total tibial, total non-erythroid and total erythroid cellularity, as well as proerythroblast, basophilic erythroblast, polychromatophilic erythroblast and orthochromatic erythroblast numbers. In the peripheral blood, % reticulocytes, numbers of red blood cells per cmm. and hematocrits were determined. Data showed that 1) Myleran significantly lowered all parameters except the basophilic erythroblasts in the marrow and reticulocyte compartments by day 4 and in the peripheral blood by day 9; 2) During the day 9, 15, and 22 sampling periods: a) Total tibial and total erythroid cellularities as well as the differentiated erythroid cell numbers show no significant differences from day 0 (control), b) The non-erythroid element, though significantly recovered from day 4 levels by day 9, remains significantly lower than controls on days 9-22 and shows a secondary depression on day 15 which is not significantly different than that on day 4, c) Reticulocytes show a significant reticulocytosis above controls which peaks on day 9 and persists through day 22, d) Peripheral blood parameters remain significantly below the controls through day 22; 3) All parameters recover to levels not significantly different from controls by day 30. The results are discussed in relationship to current findings on the effects of Myleran on the spleen colony forming unit (the probable pluripotent hematopoietic stem cell) and the erythropoietin sensitive cell (the erythropoietic progenitor cell).