Osteogenic potential of CR cells and BM cells. (A) Reverse-transcription-PCR analysis. CR cells were cultured in calcification medium for 21 days. The increase of osteogenic gene expressions was confirmed. ALP indicates alkaline phosphatase; BSP, bone sialoprotein; and OC, osteocalcin. (B) Both CR cells and BM cells were cultured in calcification medium for 21 days and alkaline phosphatase activity was measured (n = 3). (C) Passage 2 cells from 6 donors were replated at 100 cells per 60-cm2 dish and cultured for 14 days. Then the cells were incubated in calcification medium for an additional 21 days. Calcified colonies were stained with Alizarin Red; then the same dishes were stained with Crystal Violet. The ratio of Alizarin Red-positive colonies to the total number of colonies was calculated for each dish and Alizarin Red-positive colony efficiency is shown for young and elderly donors. The data are expressed as mean ± SD (n = 3).
