Survival of BMSC genetically modified with multiple reporter genes following implantation in the central nervous system of syngeneic immunocompetent mice. (A) Histogram overlay showing a representative flow cytometric analysis of eGFP expression by BMSC expressing the luciferase-, eGFP- and puromycin resistance genes (BMSC-Luc/eGFP/Pac, filled histogram). Parental BMSC were used as negative control (open histogram). (B) In vitro luminescence assay on parental BMSC and on clonal BMSC-Luc/eGFP/Pac. (C) In vivo real time bioluminescence imaging (BLI) of clonal BMSC-Luc/eGFP/Pac grafts in the central nervous system (CNS) of syngeneic immunocompetent mice at week 2 post-implantation. (D) In vivo real time BLI of clonal BMSC-Luc/eGFP/Pac intramuscular grafts in syngeneic immunocompetent mice at week 2 post-injection. (E) Representative histological analysis of clonal BMSC-Luc/eGFP/Pac implants in the CNS of syngeneic immunocompetent mice at week 2 post-implantation. Left picture: haematoxylin-eosin (HE) staining showing general appearance of the cell implantation site. Middle picture: direct eGFP-fluorescence indicating the BMSC-Luc/eGFP/Pac origin of the observed cell implant. Right picture: CD11b staining indicating a limited number of microglia surrounding the observed cell graft. All slides were examined using a conventional bright field microscope and digital pictures were taken under magnification as indicated by the scale bars.