Figure 4. BMP9 increases subcutaneous ectopic bone formation of hAMSCs cocultured with HUVECs. Representative images of subcutaneous ectopic bone formation of nude mice (A); Subcutaneous ectopic osteogenic bone formation were detected by micro-CT scanning to investigate the 3D iso-surface and the heat map of average mineralization density at 4 weeks. In the heat map, white represents the highest average mineral density and black represents the lowest (B); Quantified analysis results of micro-CT scanning show the effect of BMP9 on cocultured hAMSCs and HUVECs induced ectopic bone formation, and the relative values of bone volume/total volume (BV/TV), trabecular bone number (Tb. N), trabecular bone separation (Tb. Sp), trabecular bone thickness (Tb.Th), and bone mineral density (BMD) were demonstrated (C); The retrieved bone masses were subjected to Trichrome-Masson staining and H&E staining to determine the formation of trabecular bone and bone matrix (×400, bar: 50μm) (D) (*P < 0.05).