Expression of MMP-1 and TIMP-1 in irradiated mandibles during distraction osteogenesis.

The study aimed to evaluate the expression of MMP-1 and TIMP-1 in irradiated mandibles during distraction osteogenesis.Rabbits in the experimental group received preoperative radiation of 9 Gy for 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 days 7, 12, 18, and 25. Specimens were subjected to immunohistochemical examination and real-time polymerase chain reaction analysis.At day 7, expression of MMP-1 and TIMP-1 was significantly suppressed in the radiotherapy group in contrast to the control group. At day 12, expression of MMP-1 was significantly higher in the control group. At day 18, expression of MMP-1 and TIMP-1 was significantly higher in the control than in the radiotherapy group.Radiotherapy changes the expression pattern of MMP-1 and TIMP-1.