失神经支配在胫骨牵张成骨延长过程中的骨再生及Runx2表达

Denervation effects on bone regeneration and expression of Runx2 during distraction osteogenesis

背景:研究发现,去除坐骨神经会导致骨折愈合过程中新生编织骨机械硬度不足,而目前对有关失神经因素在牵张成骨过程中作用的相关报道较少。目的:构建新西兰大白兔胫骨牵张成骨模型,观察失坐骨神经对牵张成骨过程中新骨形成的影响及Runx2表达的变化。方法:成年新西兰雄性白兔24只建立兔胫骨牵张成骨延长模型,并随机分为切除坐骨神经组和保留左坐骨神经组。完成牵张6周后,用X射线、骨密度及三维CT重建技术检测已延长的胫骨,组织学分析新骨形成情况。结果与结论:影像学、组织学检查显示所有实验动物的牵张裂隙中均可发现有新骨生成,Runx2均有不同程度的表达。但与保留左坐骨神经组相比,切除坐骨神经组牵张裂隙中新生骨量较少、矿化程度低,并且Runx2表达量较低。提示失神经支配抑制牵张成骨中新骨的生成及Runx2的表达,神经支配可能在牵张成骨的新骨生成过程中起重要作用。

BACKGROUND;During the healing of fractures,removal of sciatic nerve can result in insufficient mechanical rigidity of newborn woven bone.However,there are less reports concerning the denervation effects during distraction osteogenesis.OBJECTIVE;To observe the effect of removal of the sciatic nerve on bone regeneration and the expression of Runt-related transcription factor 2（Runx2） protein during distraction osteogenesis in a rabbit model.METHODS;Twenty-four adult male New Zealand rabbits were selected and underwent left tibial osteodistraction to construct animal models of distraction osteogenesis.Before distraction,the animals were randomly divided into group R（resecting the left sciatic nerve） and group I（intact left sciatic nerve）.Six weeks after completion of distraction,the animals were killed and the lengthened tibias were harvested for radiography,three-dimensional CT reconstruction,histological evaluation,connectivity density（Conn.D） evaluation.RESULTS AND CONCLUSION;New regenerated bone was present and Runx2 protein was expressed in the distraction gaps of all animals at the end of the study,as revealed by radiography,three-dimensional CT reconstruction,and histological observation.However,less new bone formation and a lower degree of mineralization and expression of Runx2 protein were observed in group R compared with group I.The results suggest that the denervation appears to have an inhibitory effect on bone formation and the expression of Runx2 protein during distraction osteogenesis.