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Fig. 2 | Stem Cell Research & Therapy

Fig. 2

From: Conditioned media from endothelial progenitor cells cultured in simulated microgravity promote angiogenesis and bone fracture healing

Fig. 2

MG suppressed EPCs’ proliferation but activated HIF-1α/eNOS/NO axis. a MTT assay was performed to detect EPCs’ proliferation under MG or NG exposure. b Immunofluorescence staining showed the expression levels of Ki67 under NG (left) or MG (right) exposure. DAPI was for nuclear counterstain. c A cluster of angiogenic genes expression was examined by qRT-PCR after 12-, 24- and 48-h exposures of NG and MG, and GAPDH was used as the internal reference. d Western blot was employed to identify the expression of HIF-1α, eNOS and iNOS at protein levels. e Griess assay was performed to detect the NO contents in MG-CM and NG-CM after 12-, 24-, and 48-h exposures, and the concentrations were normalized to cell numbers. This experiment was repeated independently three times. Abbreviations: EPCs, endothelial progenitor cells; MG, microgravity; NG, normal gravity; DAPI, 4, 6-diamidino-2-phenylindole; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; HIF-1α, hypoxia-induced factor-1α; eNOS, endothelial nitric oxide synthase; iNOS, inducible nitric oxide synthase; NO, nitric oxide; VEGF, vascular endothelial growth factor; MMP-9, matrix metalloproteinase 9; PDGF-B, platelet-derived growth factor-B; Ang-2, angiogenin-2. Data were presented as the mean ± standard deviation. *P < 0.05, **P < 0.01, and ***P < 0.001

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