Identification of rat BMSCs and cell viability assay
Adherent cells were observed in culture dish after 3 days of incubation. Cells grew in colonies, and reached 80% confluence on the 7th day. These cells were designated as P0 cells. The P3 cells were uniform in shape, fusiform mainly, and grew in whirlpool shape (Fig. 1A). As indicated in Fig. 1B, at 24 hours, 100 and 200 µM CORM-3 significantly enhanced the cell viability compared with the control (P < 0.05), whereas 400 µM CORM-3 had no significant effect on the cell viability compared with the control (P> 0.05). No significant difference of cell viability was found between any two groups on 48 and 72 hours (P > 0.05). Cells were induced to differentiate into osteoblasts or adipocytes. The mineralized nodules was visualized by alizarin red staining (Fig. 1C) and lipid droplets were identified by oil red O staining (Fig. 1E). Control groups were negative for alizarin red (Fig. 1D) and oil red O staining (Fig. 1F). Cells were seeded at low density and cultured for 10 days. After crystal violet staining, cell clone was seen by the phase-contrast microscope, and the clone formation rate was (24.3 ± 2.78) % (Fig. 1G-H).