Fig. 5. Optical microscope images of MC3T3-E1 cells in chemotaxis assay after treated with control group (A and B), S group (C and D) and S-B group (E and F) for 72 h (A, C and E) and 120 h (B, D and F). (G) shows the optical density (OD) of control group and experimental groups in chemotaxis assay. *Significantly different from control group (p < 0.05). Scale bar = 200 μm.