Osteogenic differentiation of CPSCs. After induction for 14 days, the morphology of the cells changed significantly, from a fusiform appearance to a larger size and more polygonal shape. A–C, the induced cells were alizarin red positive (100×). D, RT-PCR revealed the expression of the osteoblast-specific genes lane 1 OPN, lane 2 Runx2, lane 3 ALP, GAPDH (lane 4 and lane 8) in cells from the induced group, whereas these genes were not expressed in cells from the control group (lane 5-7). GAPDH served as the internal control.