Expression of Bone Morphogenetic Protein, Vascular Endothelial Growth Factor, and Basic Fibroblast Growth Factor in Irradiated Mandibles During Distraction Osteogenesis

Purpose: The present study evaluated the expression of bone morphogenetic proteins (BMPs)-2, -4, -7, vascular endothelial growth factor (VEGF), and basic fibroblast growth factor (bFGF) in irradiated mandibles during distraction Osteogenesis. Materials and Methods: A total of 24 rabbits were randomly assigned to the control and experimental groups. Each rabbit in the experimental group underwent preoperative radiation to 9 Gy in 5 fractions. After 1 month, all rabbits underwent osteotomy and distraction osteogenesis with 7 days of latency. Three rabbits in the control and experimental groups were killed at day 7 (end of the latency period), day 12 (middle of active distraction), day 18 (end of active distraction), and day 25 (1 week after consolidation). The specimens were used for immunohistochemical staining and real-time polymerase chain reaction analysis. Results: Histologically, at day 25, cortical bone formation was much better in the control group than in the radiotherapy group. In the radiotherapy group, the bone spicules were aligned in the direction of tension stress. At clay 12, the expression of BMP-2, -4, and -7 was elevated in the radiotherapy group compared with the control group. At day 25, the expression of BMP-2 was significantly greater in the radiotherapy group. At day 7, the expression of bEGF was significantly suppressed in the radiotherapy group. At day 12, the expression of bFGF and VEGF was significantly elevated in the radiotherapy group compared with the control group. At day 25, the expression of VEGF was significantly greater in the radiotherapy group. Conclusions: The results of our study have shown that radiotherapy changes the expression pattern of BMPs, VEGF, and bFGF. (C) 2011 Published by Elsevier Inc on behalf of the American Association of Oral and Maxillofacial Surgeons. J Oral Maxillofac Surg 69:2860-2871, 2011