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目的 :建立SD大鼠胫骨牵张模型,研究Wnt/β-catenin通路在大鼠胫骨牵张成骨中的作用。方法 :建立SD大鼠胫骨牵张模型,以0.15 mm/12 h的速率延长胫骨。实验组大鼠牵张期每天在牵张间隙注射rrDkk1(recombinant rat Dkk1,25μg/kg),稳定期每3 d注射1次。对照组大鼠相同时间接受相同剂量生理盐水注射。于牵张第1、3、6、12天和稳定期第10天获取牵张骨痂标本,进行实时定量荧光PCR、Western印迹和免疫荧光检测。稳定期6周后获取牵张骨痂标本,进行X线检测、双能X线骨密度测定、显微CT和组织学检测。采用SPSS16.0软件包对数据进行统计学分析。结果:对照组中,多种Wnt配体、辅因子、受体和抗体在牵张骨痂区广泛表达,并在牵张期表达上调。实验组在rr Dkk1作用下,这些因子中大部分mRNA和蛋白质水平表达显著下调(P<0.05)。组织学和显微CT检查显示,rrDkk1组的牵张愈合区无成熟的骨愈合。结论:Wnt/β-catenin通路参与了牵张成骨全过程,临床进行牵张成骨术时应避免Wnt/β-catenin通路受到抑制。
OBJECTIVE: To establish the tibial distraction model of SD rats and study the role of Wnt / β-catenin pathway in tibial distraction osteogenesis in rats. Methods: The tibial distraction model of SD rats was established and the tibia was extended at a rate of 0.15 mm / 12 h. Rats in the experimental group were injected with rrDkk1 (25μg / kg, rgDK1) every day during the stretch phase and injected once every 3 days in the stable period. Control rats received the same dose of saline at the same time. At the 1st, 3rd, 6th and 12th days of distraction, and on the 10th day of the stable period, the distraction callus specimens were obtained, and real-time quantitative PCR, Western blot and immunofluorescence were performed. After 6 weeks of stabilization, distraction callus specimens were obtained for X-ray examination, dual energy X-ray absorptiometry, micro CT and histological examination. SPSS16.0 software package for statistical analysis of the data. RESULTS: In the control group, a wide range of Wnt ligands, cofactors, receptors and antibodies were widely expressed in the stretch-callus area and up-regulated during stretch. The experimental group under rr Dkk1, most of these factors mRNA and protein levels were significantly reduced (P <0.05). Histology and micro-CT examination showed that there was no mature bone healing in the distraction healing area of the rrDkk1 group. CONCLUSION: The Wnt / β-catenin pathway is involved in the whole process of distraction osteogenesis. Wistar / β-catenin pathway should be avoided in the process of distraction osteogenesis.