[Repair of mandibular central fissures in rabbits with hBMP-2 gene modified tissue engineered bone]

To evaluate the effectiveness of the tissue engineered bone substitute loaded with periosteal-derived osteoblasts (POBs) transfected by adenovirus mediated human bone morphogenetic protein-2 gene (Ad-hBMP-2) in the repair of rabbit mandibular central fissures.

45 rabbits with the soft tissue in the mandibular central fissures removed were randomly divided into 5 groups, group I: Ad-hBMP-2 transfected POBs/bioglass group (n=10); group II: adenovirus mediated enhanced green fluorescent protein (Ad-EGFP) gene transfected POBs/bioglass group (n=10); group III: untransfected POBs/bioglass group (n=10); group IV: single bioglass group (n=10); group V: control group (n=5). The above bone substitutes were implanted in the rabbit mandibular central fissures respectively except group V. The samples were studied by gross, X-ray, histomorphology, histomorphometrical analysis and biomechanics after 2, 4, 8, 12 weeks respectively. One-way ANOVA was used for statistical analysis.

In gross view, the rabbit mandibular central fissures in group I were replaced by new bone including cortical bone from the 4th week. X-ray examination showed that the higher bone density was found in the rabbit mandibular central fissures of group I 4 to 8 weeks after implantation. Histomorphometrical analysis showed much more new bony callus in group I than in other groups (P<0.01). The maximal anti-bending load and bending rigidity of the implanted bone substitute of group I were significantly higher than those of group II, III and IV (P<0.01).

The tissue engineered bone substitute loaded with POBs transfected by human BMP-2 gene could get the best result in the repair of rabbit mandibular central fissures, therefore, it is likely to be used in the repair of alveolar clefts.