摘要目的 探讨磁力诱导细胞靶向移植(MagIC-TT)技术在介导治疗性荧光基因标记细胞进入骨组织内部修复小鼠骨缺损中的效果及其作用机制. 方法 对比磁化与未磁化绿色荧光蛋白标记的小鼠骨髓基质干细胞(GFP-BMSCs)(n=3)的生物学特性和靶向迁移能力.将GFP-BMSCs以MagIC-TT法负载到组织工程骨中(实验组,n=5),再植入红色荧光蛋白转基因小鼠的大段股骨缺损模型中修复骨缺损,以未接种细胞的组织工程骨(对照组,n=5)及仅用髓内钉固定的空白组(n=3)为对照.术后3个月分别从X线片、显微CT、半固体脱钙和组织学等方面分析骨修复的效果和机制. 结果 磁化与非磁化GFP-BMSCs的吸光度值(0.760±0.029、0.733±0.033)、存活率(87.9％±1.0％、87.4％±2.0％)比较差异均无统计学意义(P＞0.05),但经磁化的GFP-BMSCs迁移率高于非磁化的GFP-BMSCs,差异有统计学意义(P＜0.05).术后3个月X线片结果显示:实验组小鼠支架降解,股骨缺损部位近端和远端由新生骨组织相连;空白组术后无新骨形成;对照组见少量骨形成.显微CT结果显示:实验组小鼠去除髓内钉后,股骨缺损区形成稳定的新生骨组织.半固体脱钙实验结果显示:支架材料内的GFP-BMSCs在新生骨髓腔与软骨陷窝中分布密集,红色荧光蛋白受者细胞贯穿其中,即供者细胞和受者细胞都共同参与了新生骨的形成. 结论 MagIC-TT技术可以介导治疗性细胞深入骨组织,修复小鼠骨缺损取得了良好疗效;红、绿双重荧光蛋白基因标记配合半固体脱钙等技术可观察到供、受者细胞共同参与了骨修复.

abstractsObjective To investigate the effect of magnetic-induced cell targeted transplantation (MagIC-TT) on repair of bone defects in mice using therapeutic fluorescent gene labeled cells into bone tissue and its mechanism.Methods The proliferation,apoptosis and targeted migration ability were compared between magnetized and unmagnetized murine bone marrow stromal cells labeled with green fluorescent protein (GFP-BMSCs) (n =3).GFP-BMSCs were loaded into tissue engineering bone (TEB) by MagIC-TT in the experimental group (n =5) before the TEB was transplanted into the large femur defects in the model of red fluorescent protein (RFP) transgenic mice.In the control group (n =5) TEB was not loaded with GFP-BMSCs while in the blank group (n =3) the large femur defects were only fixated with intramedullary nails.The effects and mechanism of bone repair were explored 3 months after surgery using X-ray,micro-CT,semi-solid decalcification (SSD) and histology,respectively Results There were no significant differences between magnetized and non-magnetized GFP-BMSCs in proliferation (0.760 ±0.029 versus 0.733 ±0.033) or in survival rate (87.9％ ±1.0％ versus 87.4％ ±2.0％) (P＞ 0.05),but the mobility of magnetized GFP-BMSCs was significantly higher than that of non-magnetized GFP-BMSCs (P ＜ 0.05).The X-ray 3 months after surgery showed that the scaffolds in the experimental group were degraded and that the proximal and distal ends of the femoral defects were connected by new bone tissue.No new bone formation was found in the blank group while a small amount of bone formation was observed in the control group.The Micro-CT showed that stable new bone tissue formed in the femur defects after removal of intramedullary nails in the experimental group.The SSD showed that GFP-MSCs were densely distributed in the scaffolds with red fluorescent protein (RFP) recipient cells penetrating them,indicating involvement of both donor and recipient cells in the formation of new bone.Conclusions MagIC-TT can be used to promote introduction of therapeutic cells into bone tissue to achieve a fine effect on repairing bone defects.Dual fluorescence gene marking combined with SSD shows that both donor and recipient cells may take part in the bone repairing.