双基因转染兔骨髓基质干细胞与胶原/羟基磷灰石复合修复骨缺损及对假体-骨界面整合的影响

目的 构建假体周围骨缺损模型,将慢病毒介导的骨形态发生蛋白2 （BMP-2）和转化生长因子β3 （TGF-β3）双基因转染兔骨髓基质干细胞（MSCs）与胶原/羟基磷灰石复合,后植入假体周围,观察其对假体-骨界面骨整合的影响.方法 成年健康清洁新西兰白兔24只,雌雄不限,体重2.5～3.5 kg,于两侧股骨髁间造成纵向骨缺损,植入光滑钛合金假体后保持骨假体周围2 mm骨缺损,共48侧,实验组（左侧）及对照组（右侧）各24侧,采用压缩植骨技术,重建股骨髁假体周围骨缺损,分别植入组织工程骨（双基因组）、单纯胶原/羟基磷灰石（细胞组）,打压紧密并完全覆盖植入体.于术后4、8、12周时麻醉法分别处死8只兔子,行大体观察、X线观察、组织形态计量学及生物力学测定评估组织工程化骨修复骨缺损的能力及对假体-骨界面骨整合的作用.结果 术后4周,对照组、实验组X线表现无显著差别,假体周围主要为纤维结缔组织,假体骨结合强度分别为0.3388±0.7206,0.6845±0.7186,差异有统计学意义（P＜0.01）,假体骨接触率均为0；术后8周,实验组X线表现见假体周围有新骨形成,对照组、实验组假体骨结合强度分别为0.6468±0.7852,1.1824±0.0800,假体骨接触率分别为（5.93±0.60）％,（23.35±3.76）％,二者差异均有统计学意义（P＜0.01）；术后12周实验组X线表现见假体周围为骨组织,组织学所见植入体周围为连续性骨接触,对照组、实验组假体骨结合强度分别为1.4419±0.1021,2.7622±0.1802,假体骨接触率分别为（15.27±2.34）％,（39.76±1.85）％,假体结合强度与假体骨接触率均高于对照组,差异均有统计学意义（P＜0.01）.对照组、实验组假体骨结合强度及假体骨界面骨接触率随着时间的延长而增大,术后8周与4周比较,术后12周与8周比较,数值均增高,有显著性差异（P＜0.01）.结论 组织工程化骨修复假体周围骨缺损,可促进假体周围新骨形成,提高假体-骨界面骨整合,改善假体稳定性.

Effects of prosthesis-bone interface integration of compound double gene transfection rabbit MSCs and collagen/hydroxyl apatite to repair bone defect

Objective To construct prosthesis surrounding bone defect model,forming slow virus mediated BMP-2 and TGF-β3 double gene transfection rabbit MSCs and collagen/hydroxyl apatite complex and implanting to prosthesis around,to investigate the effects of the prosthesis-bone interface bone integration.Methods Longitudinal bone defects were caused between condyle of both femurs of 24 adult clean New Zealand rabbits,male and female unlimited,weight between 2.5 kg and 3.5 kg.Smooth titanium prosthesis were inserted and a bone defect 3 mm wide around prosthesis was preserved.Then the total of 48 defects were divided into 2 groups,each of the experimental group （left）and control group（right） 24 defects.The compression and graft technology was applied to reconstruct bone defects around prosthesis,which were respectively implanted tissue engineering bone,pure collagen/hydroxyl apatite and pressed closely and completely covered implants.Respectively on postoperation 4,8,12 weeks,anesthesia methods were used to put 8 rabbits to death.The general observation,X-ray examination,histomorpbology,histomorphometric and biomechanical examination were applied to evaluation the abilities of using tissue-engineered bone to repair bone defects and effects of osseointegration of the bone-implant interface.Results After 4 weeks,experimental group and the control group,the X-ray was showed there was no significant difference,and mainly collagen/hydroxylapatite high-density shadow around the prosthesis and bone-implant surface bonding strength were respectively 0.3388 ± 0.7206,0.6845 ± 0.7186,the differences was statistically significant （P ＜ 0.01）,bone-toimpact contact（BIC） was 0;After eight weeks,X-ray examination was showed that new bone formation was found on the impact surface,for the control group and experimental group,bone-implant surface bonding strength were respectively 0.6468 ±0.7852,1.1824 ± 0.0800,BIC were respectively （5.93 ± 0.60） ％,（23.35 ± 3.76） ％,the differences were statistically significant（P ＜0.01） ;After 12 weeks X-ray examination was showed that bone tissue was found implantation,histological was showed that implantation surface mainly was continuous bone contact,for the control group and experimental group and,bone-implant surface bonding strength were respectively 1.4419 ±0.1021,2.7622 ±0.1802,BIC were respectively（15.27 ±2.34）％,（39.76 ± 1.85）％,for experimental group,both boneimplant surface bonding strength and BIC were higher than those in the control group,the differences were statistically significant（P ＜ 0.01）.Control group and experimental group,bone-implant surface bonding strength and BIC increased with the extension of time.By contrast the 12 weeks and 8 weeks,amount was respectively higher than the 8 weeks and 4 weeks,there was significant difference（P ＜0.01）.Conclusions Tissue engineering bone could repair bone defect around prosthesis,promote prosthesis surface new bone formation,improve prosthesis-bone interface bone integration,and improve the stability of the prosthesis.