血管生成素-1转染骨髓间充质干细胞在兔骨缺损修复及血供重建中的作用

摘要

背景:血管生成素-1(angiopoietin-1,Ang-1)在血管重建及创伤修复中发挥重要作用,对其在组织工程骨修复及血供重建中的作用研究较少.目的:研究转染血管生成素-1基因的骨髓间充质干细胞(bone mesenchymal stem cells,BMSCs)对兔骨缺损的修复作用.设计:自身对照的实验研究.地点和对象:实验地点为上海交通大学附属第六人民医院动物实验中心.30只6月龄健康新西兰兔作为实验对象.干预:以脂质体介导pCDNA3-Ang-1质粒转染体外分离培养的兔BM-SCs,与TCP陶瓷复合,修复兔桡骨15 mm长节段性骨缺损.以未转染细胞组作自身对照,进行观测.主要观察指标:电镜观察细胞与TCP材料复合生长情况,毛细血管生长及新骨形成通过组织学方法检测,局部血供及代谢利用核素扫描进行分析.结果:细胞与TCP材料复合后生长良好.组织学检查见转染细胞组毛细血管生长及新骨形成活跃,核素扫描见实验侧局部血供丰富、代谢旺盛,99Tcm放射性计数在作用后4,8,12,24周分别为67.74±17.29,87.39±22.42,93.51±24.25,116.43±28.67,与对照侧(35.33±14.48,51.67±17.36,72.47±22.13,89.79±24.71)组间差异有显著性意义(t=2.80～4.22,P＜0.05).结论:Ang-1转染细胞组血供增加和骨修复加速,与细胞因子局部定向释放,加强血管形成及骨代谢有关.Ang-1修饰的BMSCs预构人工骨有助于加速骨缺损的修复.%BACKGROUND: Angiopoietin-1 (Ang-1) plays an important role in vascular reconstruction and wound renovation. However, its effect on bone renovation in tissue engineering and neovasclarization has not been well studied.OBJECTIVE: To study the effect of bone marrow mesenchymal stem cells (BMSCs) transfected with Ang-1 on the renovation of bone defects in rabbits.DESIGN: An auto-control experimental study was conducted.SETTING and PARTICIPANTS: The experiment was completed at the Animal Experimental Center of the Sixth Affiliated Hospital of Shanghai Jiaotong University. Thirty healthy New Zealand rabbits of six months were treated.INTERVENTION: The rabbit BMSCs cultivated in vitro were transfected with pCDNA3-Ang-1 plasmid mediated by liposome and combined with tricalcium hosphate (TCP) ceramics to renovate the long segmental bone defects (15 mm) in rabbit radii. The untransfected BMSCs were used as auto-control.MAIN OUTCOME MEASURES: The growth of BMSCs combined with TCP materials were observed by electromicroscope scanning and the capillary growth and new bone formation detected by histological methods. The local blood supply and the metabolism were analyzed by SPECT.RESULTS: The growth of BMSCs combined with TCP materials was favorable in experimental group. The capillary growth and new bone formation were active as shown by histological examination and the local blood supply was abundant with active metabolism detected by SPECT. The 99Tcm radiocounting was 67.74 ± 17.29, 87.39 ±22. 42, 93.51 ±24.25, 116. 43 ±28.67 respectively in experimental group and 35.33 ± 14. 48, 51.67 ±17.36, 72.47 ±22. 13, 89.79 ±24.71 in control group 4, 8, 12, 24 weeks after the implantation. The difference between these two groups was statistically significant ( t = 2. 80 - 4.22, P ＜ 0.05).CONCLUSION: The increase of blood supply and acceleration of bone renovation in the experimental group are related to the local oriented release of cell factors, which enhance the formation of blood vessels and bone metabolism. Artificial bone pre-constructed by BMSCs transfected with Ang-1 can accelerate the renovation of bone defects.