基因修饰的组织工程骨联合血管束植入修复节段性骨缺损

Repair of segmental bone defect by using gene modified tissue engineering bone combined with vascular bundle implantation

目的评价骨形态发生蛋白2(BMP-2)基因修饰的组织工程骨联合血管束植入修复节段性骨缺损效果。方法分离培养兔骨髓基质干细胞,经BMP-2基因转染后复合异种骨支架体外构建基因修饰的组织工程骨。建立兔双侧桡骨缺损(2．0cm)模型,采用4种方法修复：A组：基因修饰的组织工程骨+血管束植入；B组：基因修饰的组织工程骨；C组：无基因修饰的组织工程骨+血管束植入；D组：单纯支架。术后4、8、12周行X线检查、计量组织学检查、生物力学测定和微血管墨汁灌注等观察血管形成及成骨情况。结果A组缺损区在成骨活跃程度、再生骨量等方面均显著优于其他组,血管束发出分支向移植骨内长入,血管再生旺盛,其骨缺损得到了较彻底的修复。B组在BMP-2基因诱导下成骨速度和质量优于C组；而D组缺损内主要形成纤维组织。结论BMP-2基因治疗联合血管束植入具有良好的成骨及血管化效果,对骨不连、长段骨缺损的治疗具有重要意义。

Objective To evaluate the effects of bone morphogenetic protein 2 （BMP-2） gene modified tissue engineering bone combined with vascular bundle implantation in repairing segmental bone defect. Methods The isolated rabbit bone marrow stromal cells （MSCs） , after being transfected by adenovirus carrying BMP-2 gene （Ad-BMP-2）, were seeded on bovine cancellous bone scaffolds （BCB） to construct gene modified tissue engineering bone. The rabbit models with radial defects （2.0 cm long） were made and repaired with four methods including gene modified tissue engineering bone with vascular bundle implantation （Group A）, gene modified tissue engineering bone （Group B）, nongene modified tissue engineering bone with vascular bundle implantation （ Group C ）, and only BCB scaffolds （ Group D）. After 4, 8, and 12 weeks of operation, X-ray, histological examination, biomechanics analysis and capillary vessel ink infusion were conducted to observe angiopoiesis and osteogenesis. Results Group A gained better effect in the volume and activity of new bones than other groups, with vascular bundle sending out new branches into the transplanted bones and productive regeneration of capillary vessel. The defect in Group A was repaired satisfactorily. Group B showed better effect in speed and quality of bone formation than Group C under induction of BMP-2 gene. Mainly fibrous tissues but not new bones were observed in Group D. Conclusion BMP-2 gene therapy with vascular bundle implantation has very strong osteoinduction ability and quite good vascularization effect and is of great value to the treatment of bone nonunion and bone defects.