骨折愈合过程中低氧诱导因子-1α的表达及其调节作用  

Expression and regulatory mechanism of hypoxia inducible factor-1α during fracture healing

作　　者：罗涛[1] 齐进[1] 周琦[1] 王君[1] 王晋申[1] 魏立[1] 刘晓东[1] 邓廉夫[1] 

机构地区：[1]上海交通大学医学院上海市伤骨科研究所上海市中西医结合防治骨与关节病损重点实验室,上海200025

出　　处：《上海交通大学学报（医学版）》2009年第8期902-908,共7页Journal of Shanghai Jiao tong University:Medical Science

基　　金：国家自然科学基金(30672145);上海市科委重点发展基金(06DZ22020);上海市科委研发基地能力建设专项基金(07DZ22008)~~

摘　　要：目的探讨骨折愈合过程中低氧诱导因子-1α（HIF-1α）的表达及其调节作用。方法建立小鼠胫骨骨折模型，骨折后1、3、7、14、21、28d取材，应用X线摄片、Micro-CT和四环素荧光双标记技术，观测骨痂组织的演变和新骨形成状况；采用RT-PCR、Western blotting和免疫组织化学方法，检测骨痂组织细胞HIF-1α、血管内皮生长因子（VEGF）和成骨性标志物（Runx2和ALP）的表达状况，分析HIF-1α与骨折愈合进程的关系。结果在早期骨痂组织中，募集于骨折处的细胞以及由此演化的成骨细胞、软骨细胞及骨细胞在低氧环境中均表达HIF-1α。骨折后第7天，HIF-1α阳性细胞百分率达到峰值，持续高表达7d后逐渐下降，骨折后第28天基本恢复至骨折前水平；细胞VEGF表达特征的变化与HIF-1α的表现相似；早期骨痂细胞的骨形成功能活跃，骨痂体积较大，至骨折后14d达到峰值后随骨改建的发生而逐步减小，骨痂矿化沉积主要发生于骨折愈合的中晚期（14—28d）。结论骨折愈合过程中，参与骨折愈合的细胞属低氧感应细胞并表达HIF-1α；HIF-1α可调节细胞自身的状态，通过调控早期骨痂细胞的功能和刺激血管新生而参与调节骨折的愈合。Objective To explore the expression and regulatory mechanism of hypoxia inducible factor-1α（HIF-1α） during fracture healing. Methods Mouse models of tibia fracture healing were established, and callus samples were collected 1, 3, 7, 14, 21 and 28 days after fracture. The development of callus and new bone formation were evaluated with roentgenology, Micro-CT and tetracycline double labeling method, and the expression of HIF-1α, vascular endothelial growth factor （VEGF）, Runx2 and ALP in callus were detected with RT-PCR, Western blotting and immunohistochemistry. The relationship between HIF-1α and fracture healing was analysed. Results The expression of HIF-1α was detected in cells in the fracture sites as well as in evolved osteoblasts, chondrocytes and osteocytes in early callus under hypoxia. The highest expression rate of HIF-1α achieved on the 7th day after fracture, lasted for about 7 days, then decreased gradually, and returned to intact level on the 28th day after fracture. The expression tendency of VEGF resembled that of HIF-1α. Bone formation activity was more active in early callus, and the callus volume peaked on the 14^th day after fracture and decreased gradually. The mineralization of callus mainly took place in the late healing period （14^th to 28^th day after fracture）. Conclusion Cells involved in fracture healing are hypoxia-responsive cells, which express HIF-1α. HIF-1α can regulate cell state and function, and can promote angiogenesis so as to play a crucial role in fracture healing.

关 键 词：骨折愈合 骨痂 低氧诱导因子-1Α 

分 类 号：R683[医药卫生—骨科学]