SDF-1 is down-regulated by BMSSCs following osteoinduction. (A) Semiquantitative RT-PCR of SDF-1 expression according to the relative GAPDH expression by cultured BMSSCs over time, in the presence of osteoinductive media. The mean values ± standard errors represent 4 independent experiments. Osteoinductive conditions versus the corresponding controls were analyzed using paired t test at each time point with a significance value (^*) of P < .05. (B) The dot plot represents dual flow cytometric analysis of single-cell suspensions of ex vivo–expanded BMSSCs, cultured for 48 hours in the presence of osteogenic induction media, based on the cell surface expression of STRO-1 and alkaline phosphatase antigens.