Sparing of Bone Marrow Stem Cells by Long-term Administration of Na-alginate to ²²⁶Ra Contaminated Mice

Summary

²²⁶Ra toxicity studies form the experimental basis for the estimation of radiation risk from internal emitters in man. We investigated whether treatment with Na-alginate is able to protect haemopoietic bone marrow cells against α-irradiation from ²²⁶Ra contamination. Doses from 4 to 14 μCi/kg were injected intraperitoneally in mice 12 days before the start of the treatment. Damage to marrow stem cells was assessed by the exogene clonal spleen technique. Collection of marrow cells by two methods was compared. In the lower dose groups no influence on stem cell survival is noticed, but from 9·0 μCi/kg a decrease in the number of surviving stem cells is observable in non treated animals, while in animals treated with Na-alginate fewer stem cells are damaged. These preliminary data agree with the hypothesis that Na-alginate stimulates removal of ²²⁶Ra mainly from the endosteal bone surfaces, reducing the local ²²⁶Ra dose which accounts for damage to marrow stem cells within the range of α-rays at the endosteal surfaces.