Dentin-regeneration by the differentiated bone marrow mesenchymal stem cells

Objectives: Regeneration of lost dentin is the goal of operative dentistry. At the IADR General Session in Brisbane (2006), we demonstrated that human bone marrow mesenchymal stem cells (hMSCs) differentiated into odontoblasts by stimulation with Emd-Gel and TNF-a. In the present study, we attempted to demonstrate that odontoblasts differentiating from hMSCs generated dentin under the appropriate scaffold and molecular signal in vitro.

Methods: Fifth-passage hMSCs cultured in aMEM were used for odontoblast differentiation and dentin generation. The cells were seeded and cultured in collagen gel matrix containing Emd-Gel and TNF-a. After 3, 6, and 9 wks, mRNA expressions of Osteocalcin (OCN), collagen I (COL I), and Lim homeobox protein 6 (Lhx6), which were closely related to dentin or odontoblasts, in the cultured cells or matrix were evaluated by RT-PCR.

Results: OCN, COL I, and Lhx6 mRNAs were expressed in the hMSCs or matrix culture. Additionally, the mRNA expression level of Lhx6 was constant, but that of OCN increased gradually with time.

Conclusion: These findings suggest that hMSCs with the inducing factor combination of Emd-Gel and TNF-a can differentiate odontoblasts and generate dentin.