Human umbilical-cord-blood mononucleated cells enhance the survival of lethally irradiated mice: Dosage and the window of time

The purpose of this study was to evaluate the window of time and dose of human umbilical-cord-blood (hucb) mononucleated cells necessary for successful treatment of radiation injury in mice. female a/j mice (27-30 weeks old) were exposed to an absorbed dose of 9-10 gy of 137cs γ-rays delivered acutely to the whole body. they were treated either with 1 × 108 or 2 × 108 hucb mononucleated cells at 24-52 h after the irradiation. the antibiotic levaquin was applied 4 h postirradiation. the increased dose of cord-blood cells resulted in enhanced survival. the enhancement of survival in animals that received 2 × 108 hucb mononucleated cells relative to irradiated but untreated animals was highly significant (p < 0.01). compared with earlier studies,the increased dose of hucb mononucleated cells,coupled with early use of an antibiotic,extended the window of time for effective treatment of severe radiation injury from 4 to 24-52 h after exposure. © the author 2013. published by oxford university press on behalf of the japan radiation research society and japanese society for therapeutic radiology and oncology.