Abstract:

Objective　To isolate and identify human dental pulp stem cells from third molars.Methods　Dental pulps were dissected and digested by collagenase typeⅠand dispase. The obtained single cell supernatant were harvested and cultured. Characterization of the phenotype of DPSCswas detected by immunohistochemical method and RT-PCR assay. Cell cycle was ana- lyzed by FCM. Differentiation potential of DPSCs was evaluated.Results　Colony-forming efficiency of cells derived from dental pulp tissue was 2~15 clones/103cells plated. DPSCswere found to express many different markers, including vimentin, collagen typeⅠ, GFAP, nestin and osteocalcin, while they failed to reactwithMyoD and DSPP. About 64.1% of the cellswere in G0/G1 phases, while only 35.8% in proliferation (S+G2+M). Grown in an adipogenic cocktail medium for three weeks, some DPSCs expressed fat cell markers of PPARγand LPL, and formed oil red O-positive lipid clusters in fiveweeks. After culturewith a myo- genic-inductive medium, DPSCswere found to expressMyoD, desmin and myosin, markers ofmyocyte. Long-term cultures of DP- SCs grown in differentiation inductive medium demonstrated the capacity to form Von Kossa-positive condensed nodules with high levels of calcium.Conclusion　Cells isolated from adult human dental pulp are clonogenic, and have multipotent differentiation potential, satisfying the criteria of postnatal somatic stem cell.

Key words: the third molar, dental pulp, stem cells