磷酸钙骨水泥复合自体骨髓间充质干细胞修复空心椎的实验研究

Experimental study on the repair of a vertebral of bone defect by injectable CPC and MSCs

目的探讨注射型磷酸钙骨水泥(calcium phosphate cement,CPC)复合自体骨髓间充质干细胞(MSCs)修复兔空心椎的效果。方法将16只健康新西兰大白兔随机分为组织学检查和生物力学检查组;在同一兔中在L1-L7中随机各取3个椎体建立空心椎模型,分别植入CPC/MSCs复合材料为实验组、单纯CPC为阳性对照组、模型内不加任何物质为阴性对照组。观察术后8周的组织形态学改变和生物力学测定各实验椎体、正常椎体对照组和未实验空心椎模型组的压缩强度值和刚度值。结果(1)术后8周组织学所见为实验组炎症细胞浸润少,从纤维结缔组织增生活跃到膜内化骨形成新骨明显,与周围骨结合良好,CPC逐渐吸收降解;阳性对照组炎症细胞浸润少,从纤维结缔组织增生到膜内化骨形成新骨样组织,与周围骨结合欠佳,CPC降解吸收慢;阴性对照组可见大量炎症细胞浸润到纤维结缔组织修复、血肿机化,及部分新生类骨质生成,血供丰富。(2)正常椎体对照组、实验组、阳性对照组和阴性对照组平均强度和刚度比较P<0.01,而正常椎体对照组与实验组比较P>0.05;阳性对照组与正常椎体对照组比较P<0.01。结论CPC/自体MSCs复合后有持久的骨诱导作用,加速骨的生长并能协同加快CPC的降解,使其与新骨形成后的生物力学相匹配。

Objective To investigate the histological and biomechanical properties of the compound of injectable CPC and autoallergic mesenchymal stem cells（MSCs）,using a rabbit vertebral bone defect model.Methods Sixteen healthy New Zealand white rabbits were involved in this study.Eeah group was divided into histological examination and biomechanical inspection.Three vertebral bone defects were surgically created randomly from L1-L7 in eath rabbit,and the defects were filled with utoallergic mesenchymal stem cells/CPC composite,CPC alone or left empty as a control.At 8 weeks after surgery,general morphology and histological were observed.The average area of new bone tissue;Biomechanical properties were determined using the value of vertebral compressive strength and stiffness for all the experiment group,the normal control group and non-experimental hollow model.Results（1）Histomorphological observation：8 weeks,experimental group showed less infiltration of inflammatory cells,fibrous connective tissue proliferation new bone formation,a good combination with the surrounding bone,CPC was gradually absorbed and degradated;The curtts of positive control group was similar to those of experimental group,however,osseointegration was poor and CPC degradation and absorption was slow;negative control group showed a large number of inflammatory cell infiltration fibrous connective tissue repair,hematoma,and osteoid formation,a rich blood supply.（2）In the average strength and stiffness,the normal vertebral body control group,the experimental group and the positive control group showed significant difference when compared with negative control group（P〈0.01）;but experimental group showed no difference when compared with the normal vertebral body control group（P〉0.05）;positive control group showed significant difference when compared with negative control group（P〈0.01）.Conclusion Autoallergic mesenchymal stem cells/CPC composite can sustain bone induction,enhance bone formation and speed CPC degradation which is compatible with biomechanican after bone formation.