腭中缝牵张成骨中骨形成蛋白2的表达

Expression of bone morphogenetic protein-2 during the distraction process in midpalatal suture of rats

背景:正畸医生常常通过扩大腭中缝矫正上颌骨横向发育不足。骨形成蛋白2可以诱导骨和软骨的形成,促进牵张成骨过程中的骨重建。然而关于骨形成蛋白2在腭中缝牵张成骨中的时间空间表达规律尚不清楚。目的:观察骨形成蛋白2在大鼠腭中缝牵张成骨过程中的表达规律。方法:实验选用80只5周龄雄性Wistar大鼠,分为实验组和对照组(包括阴性对照和空白对照)。将初始力值为50g的腭中缝扩大簧黏接到大鼠两侧上颌牙列上建立大鼠腭中缝牵张模型,牵张1,4,7,14d后,采用免疫组织化学和实时定量荧光PCR方法分析骨形成蛋白2蛋白和mRNA在各加力时间点的表达。结果与结论:腭中缝扩张后骨形成蛋白2蛋白表达水平显著增加,且存在时空表达差异,主要定位于腭中缝纤维组织、软骨细胞层、骨细胞和成骨细胞胞浆及其细胞外基质。同时,骨形成蛋白2 mRNA表达也明显上调。提示腭中缝牵张力可刺激骨缝中骨形成蛋白2蛋白和mRNA的合成,在骨缝塑建过程中发挥重要作用。

BACKGROUND：Orthodontists usually use palatal suture expansion to solve the problem of maxillofacial deformity.Some studies have shown that bone morphogenetic protein-2（BMP-2） can induce bone and cartilage formation,promote the distraction osteogenesis in the process of bone remodeling under mechanical tension forces.However,underlying mechanisms of BMP-2 that drive bone formation during palatal suture expansion remain unknown.OBJECTIVE：To investigate the law of BMP-2 expression in mid-palatal suture remodeling after subjecting to tensional strain loading.METHODS：Wistar male rats of 5 weeks old,with average weight of 70-80 g,were randomly divided into 2 groups,separately,Rats in experimental group were placed on the expansion appliance,with opening loops with an initial force of 50 g applied to mid-palatal suture for periods of 1,4,7 and 14 days.After expansion,the mid-palatal suture was observed by IHC staining and real time-PCR to investigate the expression of BMP-2 protein and mRNA during mid-palatal suture remodeling after suture expansion.RESULTS AND CONCLUSION：Sections with IHC staining revealed BMP-2 was detected in the osteoblast,osteocytes,chondrocytes,also in the connective tissue cells of suture.Coincident with IHC,the result of real-time PCR demonstrated time-differential expression of the mRNA that was significantly higher than that of controls at all-time points during the expansion suture remodeling.It is suggesting that BMP-2 was susceptible to mechanical tension forces and may play an important role in the remodeling of mid-palate suture.