Survival of IM injected BMSC visualized with bioluminescence (upper row) versus confocal endomicroscopy (lower row). Immediately after IM injection a cell infiltrate was seen at the injection site. In the absence of immunosuppression, in most animals no residual cells were detectable beyond 8 days after cell transplantation. BMSC survival in mice treated with CsA was only temporarily prolonged. At day 8 post-transplantation some residual, viable cells were still observed, but the signal weakened rapidly during the second week after transplantation. No cell infiltrate was detected beyond 10 days after transplantation.