Fig. 6

MG-CM facilitated neovascularization of fracture areas in vivo. a Microfil perfusion was performed to examine the newly formed vessels of the regenerated areas followed by micro-CT scan. b Total vessel volume was calculated and analyzed based on reconstructive vessel images. c–h Immunohistochemistry staining was employed to detect the expression of CD31, VEGF-A, and MMP-9 in regenerative areas followed by quantitative analyses. Abbreviations: NG-CM, conditioned media from endothelial progenitor cells under normal gravity; MG-CM, conditioned media from endothelial progenitor cells under microgravity; VEGF-A, vascular endothelial growth factor A; MMP-9, matrix metalloproteinase 9. Data were presented as the mean ± standard deviation. *P < 0.05, **P < 0.01, and ***P < 0.001