牵张成骨整复猕猴腭裂模型成骨区骨形态发生蛋白-2的表达

Bone morphogenetic protein expression in distraction osteogenesis correction for cleft palate in Rhesus monkeys

目的观察牵张成骨术整复腭裂新骨形成的骨形态发生蛋白-2(BMP-2)表达分布规律。方法猕猴23只以外科方法建立腭裂动物模型。其中实验组动物21只,以牵张成骨术整复其腭部软硬组织缺损,至骨运送盘移动关闭裂隙后原位固定。分别于固定期第1、2、4、6、8、12及24周取材3只实验动物,标本行免疫组化染色,观察其不同时间的表达分布,并与实验对照组及空白对照组结果对比。结果免疫组化实验表明,BMP-2于新骨形成过程中主要存在于成骨细胞胞浆中,在牵张成骨早期新生骨小梁的周围存在大量成骨细胞,染色为强阳性;4～6周时,成骨细胞进一步增多,BMP-2表达也呈现强阳性,表明成骨过程到达高峰;8周时成骨细胞数量减少,BMP-2表达趋于减弱;至12周时,成骨过程已基本完成,免疫组化染色基本无着色。结论术后固定成骨期内,BMP-2的表达与分布是一个由弱变强,达到成骨高峰后,随着新骨改建成熟又逐渐趋弱的动态变化过程。

Objective 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.Methods 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.Results 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.Conclusion 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.