Matrix Metalloproteinase-1 and Transforming Growth Factor-beta1 Expression during Distraction Osteogenesis and Fracture Healing of the Rat / 대한정형외과학회잡지

ABSTRACT

PURPOSE: To evaluate the temporal and spatial expression of Transforming Growth Factor-beta1 and Matrix Metalloproteinase-1 in distraction osteogenesis and fracture healing models. MATERIALS AND METHODS: Distraction osteogenesis was performed on the tibial diaphyses of Sprague- Dawley rats (latent period for 1 week, distraction for 2 weeks). The rats were euthanized at each week and the level of mRNA expression was assessed by real-time RT PCR and immunohistochemical staining. RESULTS: Although the level of TGF-beta1 mRNA and MMP-1 mRNA expression was increased during distraction osteogenesis and fracture healing, the level of mRNA expression was significantly higher in the distraction phase in the distraction group than in the fracture healing group at the same phase. After the distraction phase, the level of mRNA expression in both groups decreased to the base line. The peak expression of mRNA was followed by that of TGF-beta1 mRNA. Immunohistochemical staining revealed that TGF-beta1 was expressed mainly in the osteoblast and endothelial cells, and MMP-1 was expressed mainly in the endothelial cells of the vessel. CONCLUSION: There is specific time sequence in the expression of TGF-beta1 and MMP-1 during fracture healing and distraction osteogenesis. These results suggest that TGF-beta1 expression might be associated with the angiogenesis induced by MMP-1 expression during new bone formation.