The BMP signaling and its Smads in mandibular distraction osteogenesis

Aim:  The aim of the present study was to clarify the mechanism of signal transduction of bone morphogenetic proteins (BMPs) through their specific down signaling molecules Smads inducing bone formation in response to mechanical stimulus during distraction osteogenesis (DO) in the rat mandible.
Materials and methods:  Osteotomy of the left mandible was performed in 45 rats. Thirty rats underwent mandibular distraction (protocol; 5 days latency, 8 days distraction, and 2 weeks consolidation) while 15 rats served as non-distracted (fracture healing) group. The expression of BMPs-2,-4 and Smads 1, 5, and 8 were evaluated in the new regenerate area using immunohistochemistry.
Results:  Expressions of BMPs-2,-4 and Smads 1, 5, and 8 were moderate during latency, significantly increased during distraction and decreased towards consolidation period.
Conclusions:  The enhanced expression of BMPs and its Smads during distraction compared to the non-distracted group suggests the possible role of BMP signaling pathway in translation of mechanical forces into biological results during DO.