Low level arsenite exposures suppress the development of bone marrow erythroid progenitors and result in anemia in adult male mice

Epidemiological studies report an association between chronic arsenic (As) exposure and anemia in men, and women who are predisposed to anemia. The purpose of these studies was to determine whether a 60 d drinking water exposure of adult male C57BL/6J mice to 0, 100, and 500 ppb arsenite (As⁺³) results in anemia due to alterations in erythroid progenitor cell development in the bone marrow. Exposure to 500 ppb As⁺³ for 60 d resulted in a reduction of mean corpuscular hemoglobin (MCH) levels, but did not significantly alter red blood cell (RBC) counts, hemoglobin (Hgb) levels, mean corpuscular Hgb concentrations (MCHC), or mean corpuscular volumes (MCV). Attenuation of burst-forming unit-erythroid (BFU-E) colony formation was observed in bone marrow cells of mice exposed to 500 ppb As⁺³. The differentiation of late-stage bone marrow erythroblasts as defined by CD71 and Ter119 surface marker expression was reduced with the 500 ppb As⁺³ exposure. Mice exposed to 500 ppb As⁺³ also had elevated serum levels of erythropoietin (EPO). Collectively, these results show that exposure to low levels of As⁺³ attenuate the development of early BFU-E cells and reduce the differentiation of late-stage erythroblasts. This suppression of bone marrow erythropoiesis may be a contributing factor to the mild hypochromic anemia observed in 500 ppb As⁺³ exposed mice.