OBJECTIVETo test the capacity of the stem cells derived from human exfoliated deciduous teeth in in vitro differentiation into osteoblasts.

METHODSStem cells were isolated from the exfoliated deciduous teeth of healthy children and sorted into CD34(+)/CD117(+) cells and the remaining mixed cells using flow cytometry. After in vitro cell culture, the differentiation capacity into osteoblasts of the two groups of cells was evaluated by detecting the markers of osteoblasts using immunocytochemical techniques and fluorescent quantitative PCR. Mineralization assay was performed to identify the cell differentiation.

RESULTSThe cells isolated by typsin digestion grew in the manner of fibroblasts. After a 30-day culture of the two groups of cells, immunocytochemistry detected the expressions of osteoblast markers RUNX-2, OC, and BSP. After 40 days of cell culture, the mRNA expressions of RUNX-2, OC and BSP genes were significantly different between the two groups. At day 50 of cell culture, the CD34(+)/CD117(+) cells exhibited positivity for von Kossa's staining and alizarin red staining, but the mixed cells showed negative staining results.

CONCLUSIONThe purified CD34(+)/CD117(+) stem cells derived from exfoliated deciduous teeth of healthy children possess the capacity to differentiate into osteoblasts and form calcium deposits and mineralized nodules in vitro.