Effects of HIF-1α on MSCs in vitro . A ) Hypoxia-inducible factor-1α (HIF-1α) improved the viability and proliferation of mesenchymal stem cells (MSCs). (I) Phase contrast image of MSCs, (II) Ad-nullMSCs, (III) Ad-HIF-1αMSCs, (IV) A Cell Counting Kit-8-based colorimetric assay to quantify the MSCs viability and proliferation. B) MSCs were stained with anti-HIF-1α antibody (red) and 4, 6-diamino-2-phenylindole (DAPI) (blue). No HIF-1α was detected in MSCs group and Ad-nullMSCs. C) MSC migration assay showed HIF-1α improved the motility of MSCs. □P <0.01 vs. Ad-nullMSCs, ■P <0.01 vs. MSCs.