Fig. 2. SDF1 is a mitogen for C2C12 cells. C2C12 cells were maintained in DMEM containing 1% HS and varying concentrations of SDF1. FGF2 (20 ng/ml) served as a positive control. After 24 hours, cells were stained with antibodies against the cell-proliferation marker Ki67. The number of Ki67-expressing cells was quantified by FACS analysis and expressed as the percentage of total cell numbers. Data represent the mean ± s.d. from four independent experiments. SDF1 activated C2C12 proliferation in a dose-dependent manner (F=10.9, dF=13, P<0.002; ANOVA). Proliferative response was maximal with SDF1 at concentrations of 10 ng/ml. A comparable proliferative response was induced by FGF2 (P<0.002).