RESUMO
BACKGROUND: Dental pulp stem cells can differentiate into dentin under appropriate induction conditions, which are important seed cells i n dental tissue engineering. However, the commonly used inducers are chemical agents, which are not available for in vivo application. Mesenchymal stem cells can differentiate with the material hardness, and the physical property-induced cell differentiation is little reported. OBJECTIVE: To observe the extension characteristics and dentin differentiation potential of dental pulp stem cells from human deciduous teeth on the stiff matrix surface. METHODS: Dental pulp stem cells from naturally shed deciduous teeth were isolated, cultured and identified. Four solid gel matrixes with elasticity modulus of (9.12±0.94), (27.18±3.55), (59.37±4.05) and (86.45±5.33) kPa were made using low melting point agarose. The extension ability of passage 4 dental pulp stem cells on the surface of the above solid matrixes was detected by two-dimensional clone formation and cell scratch tests. The protein expression levels of dentin matrix protein-1, dentin phosphoprotein and dentin sialoprotein were detected by western blot assay. RESULTS AND CONCLUSION: Dental pulp stem cells from human deciduous teeth seeded on the gel matrix with extremely low and low hardness almost existed as cell clones with neat edges, and cell spreading and extension were rare. When seeded on the gel matrix with moderate and high hardness, the cloned edge of deciduous dental pulp stem cells spread and extended obviously. The cell body became large and the cell edge extended significantly. The cell scratch test revealed the similar phenomenon. When seeded on the gel matrix with moderate and high hardness, dental pulp stem cells from human deciduous teeth exhibited high expression levels of of dentin matrix protein-1, dentin phosphoprotein and dentin sialoprotein. In summary, with the increase of matrix hardness, the abilities of extension and differentiation into dentin of dental pulp stem cells from human deciduous teeth are increased gradually, which provides a method for dental tissue engineering.
RESUMO
1 cases of pleomorphic hyalinizing vascular tumor(PHAT) at the right side of neck soft tissue is reported and related literatures are reviewed.The clinical symptoms of PHAT are mild and non-characteristic,imaging examination and postoperative pathological examination may show specificity of the lesion.It is a kind of soft tissue tumor with malignant tendency.Surgical excision is the main treatment,long-term follow-up is recommended.