Experimental induction of erythroblastemia using intravenous carbonyl iron particles.

An experimental model is presented whereby erythroblastemia, the appearance of nucleated red cells in circulation, was induced reproducibly in rabbits by intravenous injection of 0.5 to 1 g/kg carbonyl iron particles (CIP). The phenomenon reached a peak in 24 to 48 hours and disappeared after a week. Erythroblastemia was associated with evidence for disseminated intravenous coagulation; both could be aborted by administration of heparin. Repeated injection of CIP was always followed by recurrence of erythroblastemia. For a period as long as 7 months, the animals tolerated repeated injections without evidence of lasting sequelae. Electron microscopic studies of marrow tissue indicated alterations in the red cell nuclei but no alterations in the endothelium of marrow sinuses into which the red cells migrate to reach the circulation. This model provides a means to study the mechanisms involved in nuclear elimination by mammalian red cells.