title: [Preparation of recombinant human bone morphogenetic protein 2 decorated beta tricalcium phosphate/collagen and preliminary studies on its properties of inducing tooth formation].
abstract: OBJECTIVE
  To explore a novel nanometer biomaterial which could induce the regeneration of tooth tissues intelligently, and to evaluate the feasibility of using this kind of biomaterial as the scaffold for tooth tissue engineering by investigating the role it plays in tooth tissue engineering.
  
  
  METHODS
  The scaffold for tooth tissue engineering containing recombinant human bone morphogenetic protein 2 (rhBMP-2) was prepared by mixing nanoscale I tricalcium phosphate (beta-TCP)/collagen particles. Forty-six 8-10 weeks old specific pathogen free Sprague Dawley (SD) rats, including 34 females and 12 males, weighing 250-300 g, were involved in this study. Tooth germs were removed under a stereomicroscope from the mandible of newborn SD rat, then digested and suspended. Scanning electronic microscope (SEM), adhesion rate of cells, and MTT assay were used to evaluate the effects of the scaffold on the tooth germ cells cultured in vitro. The tissue engineered tooth germ which was constructed by tooth germ cells and scaffold was transplanted under SD rat's kidney capsule as the experimental group (n=12); the tooth germ cells (cell-control group, n=12) or scaffold without cells (material-control group, n=4) were transplanted separately as control groups. Specimens were harvested to perform general and histological observations at 4 and 8 weeks after transplantation.
  
  
  RESULTS
  beta-TCP/collagen showed a loose and porous appearance with soft texture and excellent hydrophilicity. Tooth germ cells grew well and could attach to the scaffold tightly 3 days after coculture. The adhesion rates of tooth germ cells were 27.20% +/- 2.37%, 44.52% +/- 1.87%, and 73.81% +/- 4.15% when cocultured with scaffold for 4, 8, and 12 hours, respectively. MTT assay showed that the cell proliferation status of experimental group was similar to that of the control group, showing no significant difference (P > 0.05). Some white calcified specimens could be harvested at 4-8 weeks after transplantation. At 4 weeks after transplantation, some typical structures of dental cusp and enamel-dentin like tissues could be seen in the experimental group. Enamel-dentin like tissues also formed in some specimens of cell-control group, but they arranged irregularly. At 8 weeks after transplantation, the enamel-dentin like tissue of experimental group exhibited a mature appearance and organized structure in comparison with that at 4 weeks. And mature enamel or dentin like tissue also could be seen in cell-control group. In contrast, there was no enamel or dentin like tissue in material-control group at 4 or 8 weeks after transplantation.
  
  
  CONCLUSIONS
  rhBMP-2 decorated beta-TCP/collagen scaffold has good biocompatibility and can be used as a novel nanometer biomaterial, so it is a good choice in scaffolds for tooth tissue engineering.
authors.affiliation: Department of Oral and Maxillofacial Surgery, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou Zhejiang, 310003, PR China.
authors.forename: Wentao
authors.initials: W
authors.lastname: Zhang
authors.forename: Jianhua
authors.initials: J
authors.lastname: Liu
authors.forename: Huiming
authors.initials: H
authors.lastname: Wang
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Li
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000494:pharmacology; D055396:Bone Morphogenetic Protein 2 / Q000235:genetics*; D002130:Calcium Phosphates / Q000494:pharmacology*; D003094:Collagen / Q000494:pharmacology*; D003764:Dental Materials; D005260:Female; D006801:Humans; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000235:genetics; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds; D014083:Tooth Germ / Q000187:drug effects*; D016212:Transforming Growth Factor beta / Q000235:genetics*
chemical_list: D001672:Biocompatible Materials; D055396:Bone Morphogenetic Protein 2; D002130:Calcium Phosphates; D003764:Dental Materials; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C485817:beta-tricalcium phosphate; C499469:recombinant human bone morphogenetic protein-2; D003094:Collagen