Methods: The fetal mice of 15.5 days was used to isolate the the 1st lower molar tooth germ, and the dental papillae and sac were isolated mechanically and cells were treated enzymatically and cultured in vitro. The phase-contrast microscope was applied to record the morphology and the growth rate, and the cell characteristics were identified by immunohistochemistry method. Leukemia inhibitory factor (LIF) was used to maintain the undifferentiated station of the cells. was used. The expanded mesenchymal stem cells were seeded on Polylactic-co-glycolic acid(PLGA) porous scaffold to be cultured in vitro, and the cells-scaffold complex was implanted under the skin of nude mice to realize the capability of minerilization and differentiation of the cells seeded on the scaffold.
Results: The cultured mesenchymal stem cells were spindle-shaped or multiangular cells, of which the high activity of proliferation were observed , CD57/HNK-1 and Vimentin positive, and most of the cells express collagen type I and telomerase. D/F12 culture medium with 10% fetal cattle serum could induce the stem cells to express DSPP, which is the differentiation marker of odontoblast, The cell differentiation toward odontoblasts were observed in vitro. And finally the formation of the new-born hard tissue were observed.
Conclusion: The induction of the cells was successfully applied both in the plain culture situation and the 3D environment, of which the differentiation markers, DSPP expressed and the morphology characteristics observed. Anyhow, the mesenchymal stem cells of tooth germ and the manufactured porous degradable PLGA scaffold possessed fine prospect to be employed in tissue engineering of tooth.