Distraction osteogenesis for correction of cleft palate in rhesus-histological and fluorescent labeling study / 中华整形外科杂志

<p><b>OBJECTIVE</b>To investigate the mechanism of new bone formation in the distraction osteogenesis (DO) for correction of cleft palate (CP) in rhesus.</p><p><b>METHODS</b>CP was created by operation in 23 rhesus. The CP was corrected with DO in 21 animals as experimental group. The distraction rate was 0.8 mm per day, two times a day. The bone fragments were fixed after cleft closure, every 3 animals were sacrificed to get specimen after 1, 2, 4, 6, 8, 12, 24 weeks of fixation. 6 days before sacrifice, tetracycline was administrated for labeling (30 mg/kg).</p><p><b>RESULTS</b>The hard and soft tissue def of fixation. At the same time, the bone volume and calcification between the distraction gap increased. The cleft in the control group could not b ect was successfully closed with DO by intramembrane osteogenesis. The new formed bone was remodeling and became maturation during the period e corrected spontaneously.</p><p><b>CONCLUSIONS</b>The DO can successfully correct both the soft and hard tissue defect in CP by intramembrane osteogenesis. The fixation is important for remodeling and maturation of the new formed bone.</p>

Bone morphogenetic protein expression in distraction osteogenesis correction for cleft palate in Rhesus monkeys / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To study the expression and distribution of bone morphogenetic protein (BMP) in newly formed bone by distraction osteogenesis (DO), and to explore the mechanism of the DO bone formation and remodeling.</p><p><b>METHODS</b>The cleft palate (CP) experimental animal models (23 Rhesus monkeys) were established surgically. In experimental group (21 Rhesus monkeys), the palatal defects were corrected by means of DO at the rhythm of 0.4 mm twice per day. The specimens were retrieved under euthanasia at 1, 2, 4, 6, 8, 12, 24 weeks intervals respectively in retention period. BMP immunohistochemical study was then performed. The blank control and experimental group (each of 2 animals) were set for comparison study.</p><p><b>RESULTS</b>The immunohistochemical study showed that BMP existed mainly in cytoplasma of osteoblasts, during the process of new bone formation. In early stage of 1 or 2 weeks, abundant osteoblasts aggregating on surfaces of the new bone trabeculae with positive DAB dye were observed. Through 4 to 6 weeks, the proliferative osteoblasts with very strong positive DAB dye indicating BMP expression were recorded. From 8 to 12 weeks, the expression of BMP and quantity of osteoblasts decreased gradually while more matured new bone structures were observed.</p><p><b>CONCLUSION</b>During the whole retention period, the expression of BMP showed a tendency from weak to strong and then to final cessation, this indicated a process of formation, remodeling and maturation of osteogenesis.</p>

Ultrastructural and element spectrometric analysis of distraction osteogenesis for reconstruction of cleft palate in rhesus macaque model / 中华整形外科杂志

<p><b>OBJECTIVE</b>To study the ultrastructure and Ca/P element spectrometry of distraction osteogenesis (DO) for reconstruction of cleft palate (CP), so as to explore the osteogenesis and remodeling of new bone in situ.</p><p><b>METHODS</b>23 rhesus macaques were operated to establish animal models of CP. 2 monkeys didn't received DO as controls. The other 21 monkeys in experimental group underwent DO to correct both bony and soft tissue defects in palate. The distraction was performed at a rate of 0.8 mm/d, twice a day until the cleft was closed. After fixation for 1, 2, 4, 6, 8, 12, 24 weeks, every 3 animals were sacrificed to get the specimens at the distraction gap. The scanning electron microscopic study and Ca, P elements spectrometric analysis were adopted. There were also two unoperated animals as sham group.</p><p><b>RESULTS</b>After fixation for 1-2 weeks, the distraction gap was full of collagen fibers oriented along vector of distraction. Few trabeculae was seen at the margin area. After fixation for 4-6 weeks, active osteogenesis was presented with new formed bone trabeculae and abundant cellular component. After fixation for 8-12 weeks, the new formed bone became mature and couldn't distinguish from the normal bone. 24 weeks later, the bone between the distraction gap had a similar structure to the normal bone. Elements spectrometric analysis results indicated that in early stage of osteogenesis, the P and S peaks were relatively high while the Ca peak was much lower. During the late stage, the S peak was obviously decreased, and Ca/P ratio increased to normal level as in the empty control group.</p><p><b>CONCLUSIONS</b>The CP can be corrected by DO. The new bone between the distraction gap is formed and remodeled through intramembraneous osteogenesis.</p>

Expression of insulin-like growth factor-1 and alkaline phosphatase in the reconstruction of cleft palate with distraction osteogenesis in rhesus / 中华整形外科杂志

<p><b>OBJECTIVE</b>To investigate the osteogenesis mechanism by analysis of the expression of insulin-like growth factor-I (IGF-1) and alkaline phosphatase (ALP) in the reconstruction of cleft palate (CP) with distraction osteogenesis (DO) in rhesus.</p><p><b>METHODS</b>The CP animal models were established surgically. 21 rhesus in experimental group underwent DO to close the soft and bony defect, followed by consolidations. Every 3 animals were killed and the specimen were taken out after consolidation of 1, 2, 4, 6, 8, 12, 24 weeks. The mRNA of IGF-1 and ALP were detected with Real-time RT-PCR technique. The expression of IGF-1 and ALP was quantitatively analyzed by ELISA. The results were compared with those in control and sham groups (each of 2 animals), respectively.</p><p><b>RESULTS</b>Since consolidation, the mRNA of IGF-1 and ALP increased significantly at one week and reached the peak at two weeks, but decrease to control level after 12 weeks of consolidation. The expression of IGF-1 also increased to peak level after two weeks of consolidation. The expression of ALT increased significantly since consolidation and reach the peak value after six weeks. They all decreased to nearly control level after 8-12 weeks.</p><p><b>CONCLUSIONS</b>The palate cleft can be successfully closed with new formed bone after DO. The mechanism of bone consolidation is intramembranous bone formation.</p>

Expression of osteopontin and osteocalcin during distraction osteogenesis on rhesus with cleft palate / 中华整形外科杂志

<p><b>OBJECTIVE</b>To study the mechanism of new bone formation and remodeling of distraction osteogenesis (DO) by analysis of the expression of osteopontin (OPN) and osteocalcin (OC).</p><p><b>METHODS</b>Rhesus were operated to reconstruct the animal model of cleft palate (CP). The CP was closed by DO in experimental group(n = 21). After consolidation of 1, 2, 4, 6, 8, 12, 24 weeks, every 3 animals were killed to collect the specimens, respectively. The OPN and OC and their mRNA were detected quantitatively by Real-time RT-PCR and ELISA, respectively. The animals in control group (n = 2) and sham group (n = 2) were used as control.</p><p><b>RESULTS</b>The mRNA expression of OPN increased since 2nd week of consolidation and reached the peak at 4th week (7.59 +/- 0.37). The mRNA expression of OC was up-regulated since 4th week, and reach the peak at 6th week (7.94 +/- 0.31). Then they decreased to about the level in sham group at 24th week (P > 0.05). The OPN and OC were highly expressed during 4 to 6 weeks of consolidation. During 8 to 12 weeks, they decreased like their mRNA expression.</p><p><b>CONCLUSION</b>The intramembraneous new bone formation after DO can reconstruct the bone defect of CP. The new formed bone can be remodeled to be quite normal bone tissue.</p>