Mesenchymal and embryonic characteristics of stem cells obtained from mouse dental pulp

Objective: Several studies have demonstrated that human dental pulp is a source of mesenchymal stem cells. To better understand the biological properties of these cells we isolated and characterized stem cells from the dental pulp of EGFP transgenic mice. Methods: The pulp tissue was gently separated from the roots of teeth extracted from C57BL/ 6 mice, and cultured under appropriate conditions. Flow cytometry, RT-PCR, light microscopy (staining for alkaline phosphatase) and immunofluorescence were used to investigate the expression of stem cell markers. The presence of chromosomal abnormalities was evaluated by G banding. Results: The mouse dental pulp stem cells (mDPSC) were highly proliferative, plasticadherent, and exhibited a polymorphic morphology predominantly with stellate or fusiform shapes. The presence of cell clusters was observed in cultures of mDPSC. Some cells were positive for alkaline phosphatase. The karyotype was normal until the 5th passage. The Pou5f1/Oct-4 and ZFP42/Rex-1, but not Nanog transcripts were detected in mDPSC. Flow cytometry and fluorescence analyses revealed the presence of a heterogeneous population positive for embryonic and mesenchymal cell markers. Adipogenic, chondrogenic and osteogenic differentiation was achieved after two weeks of cell culture under chemically defined in vitro conditions. In addition, some elongated cells spontaneously acquired a contraction capacity. Conclusions: Our results reinforce that the dental pulp is an important source of adult stem cells and encourage studies on therapeutic potential of mDPSC in experimental disease model