Immunohistochemical localization of bone morphogenetic protein-signaling Smads during long-bone distraction osteogenesis.
In this study we investigated the expression of bone morphogenetic protein (BMP)-signaling Smads in distraction osteogenesis (DO). Osteotomy of the right tibia was performed in 14 skeletally mature white New Zealand male rabbits. Lengthening was started 1 week later at a rate of 0.5 mm/12 hr and was maintained for 3 weeks. Expression of Smad proteins 1, 4, 5, 6, 7, and 8 and Smad ubiquitin regulatory factors (Smurfs) 1 and 2 was evaluated in the distracted zone using immunohistochemistry. Expression of receptor-regulated Smads (R-Smads) 1, 5, and 8 showed a significant increase during the distraction phase, followed by a gradual decrease during the consolidation phase. Smad 4 showed significant expression during both distraction and the beginning of the consolidation phase. Smad 6 and Smad 7 were highly expressed during the consolidation phase. Staining for both Smurfs 1 and 2 was maximal at the end of the distraction period. Staining for all proteins was most intense in chondrocyte and fibroblast-like cells. Expression pattern of R-Smads correlated with our previously reported expression pattern of BMPs 2, 4, and 7 and their receptors. These results therefore suggest a role for the whole BMP signaling pathway including the Smad proteins in DO.
Haque
Tasima
T
Shriners Hospital for Children, Montréal, Québec, Canada H3G 1A6.
Mandu-Hrit
Manuela
M
Rauch
Frank
F
Lauzier
Dominique
D
Tabrizian
Maryam
M
Hamdy
Reggie C
RC
D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000502:physiology*; D007150:Immunohistochemistry; D008297:Male; D019857:Osteogenesis, Distraction; D011817:Rabbits; D051785:Smad Proteins / Q000096:biosynthesis*; D013977:Tibia / Q000378:metabolism*
D019485:Bone Morphogenetic Proteins; D051785:Smad Proteins