Figure 1. Preparation of genetically labeled MSCs. (A) Schematic of lentivirus carrying luciferase and RFP reporters with an 2A connector under the control of a CMV promoter. (B) Flow cytometry for transduced MSCs (MSC-LR) for RFP. (C) MSCs-LR in cell culture, showing RFP label and nuclei by DAPI staining. (D) Bioluminescence was detected in MSCs-LR cells after luciferin exposure. (E) Osteocyte-, adipocyte- and chondrocyte- differentiation of MSCs-LR and control MSCs, validated by Von Kossa staining, Oil red O staining and Alcian blue staining, respectively. *p<0.05. N=5. Scale bar in panel C is 20μm and in panel D is 100μm.