BMP/Smads信号传导通路在兔下颌持续前导后髁突的表达

目的：探讨免下颌持续功能前导后髁突软骨中BMP／Smads信号传导通路表达与髁突改建的关系。方法：60只8周龄的日本大耳白兔，随机分成实验组（n=36）和对照组（n=24），实验组动物每日24h戴用咬合前导矫正器。实验动物分别在第3天、1周、2周、4周、8周及12周时处死并取材，用免疫组化方法观测髁突组织内BMP-2和Smad1／5、4、6的分布和表达，并对其表达进行灰度测定。结果：BMP-2和Smad1／5、4、6主要在髁突软骨过渡层和肥大层软骨细胞中表达，钙化层的软骨细胞和成骨细胞中也可见BMP-2和Smad1／5、4、6的表达。实验组兔髁突软骨BMP-2和Smad1／5、4、6的表达强度在早期高于同期对照组（P〈0．05），与髁突骨组织改建的活跃程度同步。结论：下颌持续前导后，Smad1／5、4、6作为BMP-2的细胞内信号传导分子，与下颌髁突适应性生长改建关系密切。

Expression of BMP/Smads in rabbit condylar cartilage during mandibular forward positioning

Objective: To identify the relationship between the expression of BMP/Smads in condylar cartilage and condylar growth modifications in rabbits during mandibular forward positioning.Methods: Sixty male rabbits with 8 weeks of age were randomly divided into the experimental group(n=36) and control group(n=24).The mandibles of rabbits in the experimental groups were induced to forward position by a functional appliance.The rabbits in the experimental group and control group were sacrificed after 3 days and 1,2,4,8,12 weeks,respectively.The expression of BMP-2,Smad1/5,4 and 6 in condylar cartilage was examined by immunohistochemical staining.Results: The expression of BMP-2,Smad1/5,4 and 6 was mainly found in the chondrocytes from the transitional zone and hypertrophic zone,and was also found in the chondrocytes and osteoblasts of the mineralized zone.Compared with those of the age-matched controls,the positive signals for BMP-2,Smad1/5,4 and 6 in the experimental animals were stronger at early stage(P<0.05),coinciding with the remodeling in condylar cartilage after functional appliance.Conclusion: The expression of BMP-2,Smad1/5,4 and 6 is associated with the adaptive remodeling of the condylar cartilage after functional appliance.