BMP-2及Smad1在兔下颌骨垂直牵张中的表达和意义

目的：观察BMP-2及其信号传导分子Smad1在兔下颌骨垂直牵张后新骨组织中的分布和表达,探讨其在新骨形成中的作用。方法：36只兔子随机分成6组,用自制的种植型牵张器对兔下颌骨垂直牵张,以1mm/天的速度牵张4天,分别于牵后第1天、1周、2周、4周、6周取材,6只作为正常对照组。用ABC免疫组织化学法,检测兔下颌骨垂直牵张过程中不同时期BMP-2及Smad1的表达与分布。结果：免疫组化观察,牵张结束后BMP-2及Smad1阳性信号主要在间充质细胞和新生骨小梁边缘的成骨细胞表达,表达高峰在牵张后1周,以后逐渐下降,牵张后4周在骨细胞微弱表达,6周时无表达。正常对照组无表达。结论：BMP-2及Smad1/5参与兔下颌骨垂直牵张过程,并在牵张成骨的早期起作用;Smad1/5可能介导了BMP-2在牵张成骨中的信号传导。

The expression and role of BMP-2 and Smadl in the regenerative bone of rabbits during vertical mandibular dis traction osteogenesis

Objective： To observe the expression paterns of BMP-2 and Smadl in the regenerative bone created by vertical mandibular distraction osteogenesis （DO） and to explore the role of BMP-2 and Smadl during the process of DO. Methods： 36 rabbits were randomly grouped into 6, single mandibular osteotomies were performed in 30 rabbits, and 6 rabbits used as negative control were not performed. After a latency of 4 days, the mandibles were lengthened 4mm with a rate of 1mm/d after using a custom distracto. Every 6 rabbits were killed at the first day, the first week, the second week, the fouth week, the sixth week after distraction, and the distracted calluses from all rabbits were harvested and processed for immunohistochemistry of BMP-2 and Smadl. Results： Elevated expressions of BMP-2 and Smadl were observed following mandibular distraction osteogengsis, positive straining for BMP-2 and Smadl were mainly found in the mesenchymal cells and the active osteoblasts around the newborn trabecular bone. Their strongest expression were noticed at the first week after distraction, then the expressions turned week, at the fourth weeks after distraction,only weak expression were detected in osteocytes, at the sixth weeks after distraction, the expression could be neglected. Conclusions： Both BMP-2 and Smad 1/5 parcitipate in the process of DO, they may play an important roles in the early stage of distraction, Smad 1/5 maybe transduces the signal of BMP-2.