Feasibility of Treating Irradiated Bone with Intramedullary Delivered Autologous Mesenchymal Stem Cells

Background. We aimed to explore (i) the short-term retention of intramedullary implanted mesenchymal stem cells BMSCs and (ii) their impact on the bone blood flow and metabolism in a rat model of hindlimb irradiation. Methods. Three months after 30 Gy irradiation, fourteen animals were referred into 2 groups: a sham-operated group (n = 6) and a treated group (n = 8) in which In-111-labelled BMSCs (2 x 10(6) cells) were injected in irradiated tibias. Bone blood flow and metabolism were assessed by serial Tc-99m-HDP scintigraphy and 1-wk cell retention by recordings of Tc-99m/In-111 activities. Results. The amount of intramedullary implanted BMSCs was of 70% at 2H, 40% at 48 H, and 38% at 168 H. Bone blood flow and bone metabolism were significantly increased during the first week after cell transplantation, but these effects were found to reduce at 2-mo followup. Conclusion. Short-term cell retention produced concomitant enhancement in irradiated bone blood flow and metabolism.