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Stromal cell-derived factor-1 mediates changes of bone marrow stem cells during bone repair process

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AJP Endocrinology and Metabolism

Published online on

Abstract

Osteoblasts, osteoclasts, chondrocytes, and macrophages that participate in the bone repair process are derived from hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs). However, the roles of these stem cells during the repair of injured bone tissue are still unclear. In the present study, we examined the effects of bone defect on HSCs and MSCs in bone marrow and spleen in mice and its mechanism. We analyzed the HSC and MSC populations in these tissues of a mouse with femoral bone damage by using flow cytometry. The numbers of HSCs and MSCs in the bone marrow of mice with damaged femurs were significantly lower and higher, respectively, than the numbers of these cells in the bone marrow of the contralateral intact femurs on day 2 after injury. Conversely, this effect was not observed within the spleens of mice after bone damage. Meanwhile, both intraperitoneal administration of AMD3100, a C-X-C chemokine receptor 4 (CXCR4) antagonist, and local treatment with an anti-stromal cell-derived factor-1 (SDF-1) antibody blunted the observed decrease and increase in HSC and MSC populations, respectively, within the bone marrow of injured femurs. In conclusion, the present study revealed that there is a concurrent decrease and increase in the numbers of HSCs and MSCs, respectively, in the bone marrow during repair of mouse femoral bone damage. Furthermore, the SDF-1/CXCR4 system was implicated as contributing to the changes in these stem cell populations upon bone injury.