Bone Morphogenic Protein-2 Gene Therapy for Mandibular Distraction Osteogenesis

In Brief Distraction osteogenesis (DO) requires a long consolidation period and has a low but real failure rate. Bone morphogenic proteins (BMPs) accelerate bone deposition in fractures and critical-sized bone defects, but their effects on mandibular DO are unknown. We investigated the effect of local delivery of adenovirus containing the gene for BMP-2 (Adbmp-2) on mandibular DO in a rat model. Rats (n = 54) were distracted to 3 mm over 6 days. At the start of consolidation (POD 10), Adbmp-2 or adenovirus containing the lacZgene (AdlacZ) was injected directly into the distraction zone. After 1, 2, and 4 weeks of consolidation, mandibles were evaluated for amount of bone deposition. Adbmp-2-treated specimens demonstrated an increased amount of new bone formation by radiographic, histologic, and histomorphometric analysis. This study demonstrates that local, adenovirally–mediated delivery of BMP-2 can increase bone deposition during DO, potentially shortening consolidation and enhancing DO in poorly healing mandibles, such as occurs postirradiation. In a rat mandibular distraction model, adenovirus encoding BMP-2 was injected directly into the distraction zone at the start of consolidation. Bone deposition was increased over controls by radiographic, histologic, and histomorphometric analysis.