The purpose of the present study was to observe the response and changes of cranial
suture to the distraction forces in growing goats and to examine the expression patterns of TGF-β
and BMP during suture distraction.Twenty growing goats were divided into three groups: control
(n=4), experimental (n=12), and sham (n=4). A pure titanium distractor was placed in the coronal
suture in both the sham and experimental groups. After healing, the distractor was activated for
distraction of the coronal suture at a rate of 0.5 mm/day for 8 days in the experimental group. Three
animals were killed respectively, at 0，2，4 and 8 weeks after completion of suture distraction. No
force was applied in the sham group. X- Ray examination was taken and the coronal suture samples
were harvested and processed for histological analysis and scanning electron microscopic analysis
and immunohistochemistry of TGF-β and BMP. The coronal sutures of experimental group were
separated successfully. Signs of intramembranous bone formation and remodeling were found in the
distracted suture，and the sutural structure almost return to its normal state at 8 weeks after end of
distraction. At 0 and 2 weeks after completion of suture distraction, the collagen fiber bundles were
strengthened and aligned in the direction of the distracted forces. Strong expression of BMP and
TGF-β were detected in the fibroblast-like cells and the active osteoblasts. At 4 weeks after suture
distraction, signs of intramembranous ossification were found in the edge areas of the distracted
suture, and the positive staining of BMP and TGF-β was still noted in the osteoblasts around the
newly formed bone trabeculae. This study suggests that cranial suture expansion can be achieved in
growing animal by distraction osteogenesis. Mechanical strain resulted from distractor can induce
the adaptive remodeling in the cranial suture of growing goats. It also suggests BMP and TGF-β
may play very important roles in the process of bone formation and remodeling during suture
distraction osteogenesis.
Adipose-derived stem cells transfected with pEGFP-OSX enhance bone formation during distraction osteogenesis
