RGD修饰的仿生骨膜及纳米化诱导骨促进兔脊柱融合的实验研究

Experimental study of rabbit＇s spinal fusion promoted by RGD modified mimetic periusteum combined with nanoscale osteoinductive bone

目的分析联用RGD修饰的仿生骨膜及纳米化诱导骨促进兔脊柱融合的可行性，探讨其应用潜力。方法成骨诱导化培养兔脂肪基质细胞、制备释放rhBMP-2的壳聚糖／胶原蛋白／B磷酸三钙膜材及生物衍生型复合基质，联合生物凝胶＋动态种植，构建RGD修饰的仿生骨膜与纳米化诱导骨；建立兔腰5～6横突间融合模型，移植5组：A组RGD修饰的仿生骨膜及纳米化诱导骨；B组纳米化诱导骨；C组RGD修饰的仿生骨膜、D组空白支架（nCs-PCL-β-TCP），E组自体髂骨行组织学、免疫组织化学、双能X线吸收法、手动触检及生物力学检查。结果A组骨性融合能力最强，骨矿物含量（BMC）、骨密度值（BMD）、融合率及力学指标均高于其他组，差异具有统计学意义（P〈0．05）；E、C组次之，B组融合相对延缓。D组未融合。结论RGD修饰的仿生骨膜及纳米化诱导骨能强化骨再生，通过协同诱导、引导、传导效应，促进脊柱融合。

Objective To investigate the application potential of mimetic periosteum and tissue engineered bone in promoting spinal fusion in rabbits. Methods With aid of biological gels compound and dynamic （oscillating pattern） seeding, three-dimensional construction of RGD modified mimetic periosteum was made by implanting adipose derived stromal cells （ADSCs） into rhBMP-2 mediated CsCol β-TCP membrane, nanoscale osteoinductive bone was constructed by implanting ADSCs into rh- BMP-2 mediated Cs-PCL-β-TCP matrix. Lumbar 5-6 lateral process fusion model was established using New Zealand rabbits. The rabbits were randomly distributed into 5 groups： Group A was implanted with RGD modified mimetic periosteum combined with nanoscale osteoinductive bone; group B was implanted with nanoscale osteoinductive bone; group C was implanted with RGD modified mimetic periosteum; group D used Cs-PCL-β-TCP matrix as blank scaffold, and group E was implanted with bone autograft. Histology, immunohistochemical staining, dural energy X-ray absorptiometry （DEXA）, palpation and biomeehanical examinations were performed at different time points. Results Compared to the other 4 groups, group A displayed remarkable spinal fusion： bone mineral content （BMC）, bone mineral density （BMD） and biomechanical testing were significantly better （P〈0. 05）. Group E and C came next with better spinal fusion than group B. In group D, spinal fusion was failed. Conclusions Enhanced osteogenic potential can be achieved by using RGD modified mimetic periosteum with nanoscale osteoinductive bone, which promote spinal fusion by synergistic effects of osteoinduction, osteopromotion and osteoconduction.