Combination of scaffold and adenovirus vectors expressing bone morphogenetic protein-7 for alveolar bone regeneration at dental implant defects.

The current rapid progression in tissue engineering and local gene delivery systems has enhanced applications of osseointegration in dental implants. In this study, porous chitosan/collagen scaffolds were prepared through a freeze-drying process, and loaded with an adenoviral vector encoding human bone morphogenetic proteins (BMP7). These scaffolds were evaluated in vitro by scanning electron microscopy (SEM), and human periodontal ligament cells (HPLCs) were seeded in this scaffold. We used Reverse transcription-polymerase chain reaction (RT-PCR) to determine the expression levels of osteopontin and bone sialoprotein. Alkaline phosphatase (ALP) activity was also determined. Then these scaffolds were implanted into defects on both sides of the mandible. Three months later, the animals were sacrificed and non-decalcified sections were evaluated histologically. Histomorphometric analyses were performed at the bone-implant interface using the image obtained by confocal laser scanning microscopy. Results indicated that the scaffold containing Ad-BMP7 exhibited the higher ALP activity, and the expression of osteopontin and bone sialoprotein were up-regulated. After implanting in defects around implant, the bone formation in Ad-BMP7 scaffolds was greater than that in other scaffolds at 4 or 8 weeks. This study demonstrated the potential of chitosan/collagen scaffold combined Ad-BMP7 as a good substrate candidate in bone tissue engineering.