Acceleration of consolidation period by thrombin peptide 508 in tibial distraction osteogenesis in rats

We aimed to find out whether a single local injection of two different doses of thrombin peptide 508 (TP508) could accelerate consolidation of bone in sites of tibial distraction osteogenesis in rats. Forty-eight adult male Sprague-Dawley rats were divided equally (n=16 in each group) into controls (given saline alone), and two experimental groups, given injections of TP508 10μg or 100 μg. The animals were killed on days 14 and 28 after distraction. Histomorphometric evaluation showed that the TP508 resulted in significantly larger areas of newly formed bone (p<0.003 and p<0.0001) than saline alone. At 2 weeks, more new bone had formed in the group given TP508 100 μg than in the group given 10 μg, but the difference was not significant (p=0.8). However, the difference was significant at 4 weeks (p=0.03). These findings suggest that a single injection of TP508 given at the end of the distraction period increased the degree of consolidation. The higher dose was more effective at the later time point.