The Inductive Effect Of RhBMP-2Decoratedβ-tricalcium Phosphate/Collagen On Tooth Formation: A Preliminary Study

BackgroundsAs an important branch of regenerative medicine, tooth regeneration has become a research focus in the field of oral medicine. Following classical tissue engineering techniques, a regenerated tooth with complete tooth structures has been produced in the jaw of an animal. However, there are hurdles in the regeneration of a fully functional tooth. As one of the three key components, biomaterial scaffold may be indispensible in tissue engineering. The biomaterial scaffold can provide a necessary framework and initial support for the stem cells to attach, proliferate and differentiate, and form an extracellular matrix, which allows rearrangement of the stem cells during tooth tissue engineering. Therefore, to develop an ideal biomaterial scaffold for the regeneration of a fully functional bioengineered tooth is of great significance.ObjectiveIn order to develop a scaffolding material for tooth tissue engineering, the nano (3-TCP/COL (β-tricalcium phosphate/collagen) was modified with recombinant human BMP-2(rhBMP-2). To evaluate its feasibility as a scaffold for tooth tissue engineering, the role played by the modified β-TCP/COL during tooth tissue engineering was investigated.MethodsThe scaffold for tooth tissue engineering containing rhBMP-2was prepared by mixing nanoscale P-TCP particles, collagen and rhBMP-2under certain conditions. Tooth germs were removed under a stereomicroscope from the mandible of SD(Sprague-Dawley) rat which was born no more than1day, then digested and suspended. SEM. adhesion rate of cells and MTT assay were used to evaluate the effects of the scaffold to tooth germ cells when cultured in vitro. As the experimental group, tissue engineered tooth germ which was constructed by tooth germ cells and scaffold was transplanted under the kidney capsule of SD rat. For control groups, tooth germ cells (cell-control group) and scaffold without cells (material-control group) were transplanted separately. Specimens were observed in general and treated by histological as well as immunohistochemical methods at8weeks after transplantation.ResultsPorous β-TCP/COL showed a loose and porosity appearance, softy texture and excellent hydrophilicity. Tooth germ cells grew well in the3D-environment the scaffold provided and could attach to the scaffold tightly. The adhesion rate of tooth germ cells was27.20%±2.37%、44.52%±1.87%、73.81%±4.15%when co-cultured with scaffold for4,8and12h respectively. MTT assay showed that the cell proliferation status of experimental group was similar to the control group, and there was no significant difference (P>0.05). Some calcified specimens of white color could be harvested8weeks after transplantation. At8weeks after transplantation, some typical structures of dental cusp and enamel-dentin like could be seen in experimental group. Enamel and dentin like tissues also formed in some specimens of cell-control group, but did not present a well arrangement as experimental group. In contrast, there was no enamel or dentin like tissue in material-control group. The immunohistochemical result confirmed the formation of DSPP (Dentin sialophosphoprotein).ConclusionThe rhBMP-2decorated β-TCP/COL scaffold has good biocompatibility and can be used as a novel nanometer biomaterial, so it may become a good choice as a scaffold for tooth tissue engineering.