In Vitro Expression Of Radiation-Induced Stem Cell Damage In Macrophage Differentiation
An in vitro assay using murine bone marrow cells was used to determine radiation-induced stem cell damage on subsequent in vitro macrophage differentiation. The assay system consisted of cultures of macrophage progenitor cells stimulated by the addition of L-cell conditioned medium high in CSF-1. Experimental animals were exposed to 400 rads of radiation using a Cobalt-60 source. It was found that residual stem cell damage was exhibited in vitro with a reduction of up to 63.9% on day-1 after exposure in the number of macrophage colonies arising in vitro. Proliferative compensation yielded slightly above normal levels of CFU-m by day-14, disguising the residual stem cell damage which had occurred. These findings are in line with other research on CFU's in general and CFU-e more specifically which utilized spleen cell assays. Such an assay gives information on how one specific hematopoietic cell line, CFU-m, reacts to radiation damage. It also allows a much easier method for studying hematopoietic progenitor cell damage than does lengthy histological examination with spleen cell assays.