Bone morphogenic proteins (BMPs) are important bone-induction factors, and the development of a suitable carrier for BMPs is a critical step to achieve osteoinductive function. The aims of the present study were to evaluate, at the cellular and molecular levels, the feasibility of recombinant human BMP-2 (rhBMP-2)-collagen composite scaffold and its efficiency for carrying BMP-2 in ectopic bone formation in rats.Methods:
Scaffolds with (test) or without rhBMP-2 (control) were made and implanted into the calf muscle of 16 5-weekold rats. The tissue responses to the scaffolds were examined by histology. Masson's trichrome and von Kossa stainings were performed to examine collagen matrix deposition and calci- fication at 3, 7, 10, and 14 days. Expressions of bone phenotypic markers, alkaline phosphatase, osteocalcin, osteopontin, and bone sialoprotein were detected by reverse transcriptionpolymerase chain reaction and immunohistochemistry.Results:
No detectable adverse responses were noted around the implanted scaffolds, and the area of the resorbed scaffold had been replaced by young connective tissue by 3 to 7 days in both groups. In the rhBMP-2 composite scaffold, collagen matrix deposition was found in the implanted site on day 7 and initial signs of endochondral differentiation also appeared. Mineralization and the expressions of key bone proteins were demonstrated in chondroblasts and osteoblasts at 7 to 14 days. Molecular cascades of bone induction were not shown in control specimens.Conclusion:
The rhBMP-2-atelocollagen scaffold showed excellent biocompatibility and possessed a bone-inducing capacity in rat within 2 weeks, and, thus, may provide a potential application in tissue engineering of bone tissue. J Periodontol 2007; 78:335-343.