FIGURE 1.

Irradiation caused stemness impairment of skeletal stem cells. Irradiation caused a significant reduction in the number of in situ CD105⁺ and CD140a⁺ cells in murine femurs at a radiation dose‐dependent manner (A,B). Additionally, irradiation remarkably decreased the ratios of CD105 and CD140a cells in skeletal stem cells (SSCs) in vitro (C). Furthermore, the colony‐forming unit fibroblast formation (CFU‐F) assay showed that irradiated SSCs exhibited decreased colony formation capacity relative to that of nonirradiated SSCs (D,E). Moreover, the expression of self‐renewal‐related genes, Nanog and Sox2, remarkably decreased after irradiation (F). The Cell Counting Kit 8 (CCK‐8) data demonstrated that irradiation inhibited cell proliferation (G). Further data showed that irradiation inhibited alkaline phosphatase (ALP) activity and osteogenic mineralization (H) and the expression of osteogenic genes, including Runx‐2 and OPN (I), in SSCs at dose‐dependent manner upon irradiation (H,I). Bars in A, D, and H, represent 200 μm, 500 μm, and 200 μm, respectively. *P < .05, **P < .01, ***P < .001