Effect of maternally administered sodium nitrite on hepatic erythropoiesis in fetal CD-1 mice.

A commonly used food preservative, sodium nitrite, was administered to pregnant CD-1 mice at a concentration of 0.5 mg/mouse/day. Embryotoxic and teratogenic effects on the hemopoietic tissues and skeletons of their offspring, were evaluated. Fetal mortality, resorptions, the mean number of offspring per litter, the mean weight per embryo and the incidence of skeletal malformations, were not significantly different from controls. Hemopoietic cell suspensions, prepared from the livers of treated and control 14-, 16- and 18-day embryos, were cytocentrifuged onto microscope slides and differential counts were performed after staining with benzidine and Wright-Giemsa stain. The results indicate that maternally administered Na nitrite, stimulates fetal hepatic erythropoiesis. This was manifested in a statistically significant increase in the percentage of polychromatophilic erythroblasts and mature erythrocytes at 14 and 16 days of gestation, respectively. The possibility that Na nitrite may induce fetal methemoglobinemia is discussed and mechanisms responsible for the observed erythroid stimulation, are considered.