改良复合磷酸钙骨水泥诱导分化成骨作用的体外研究

目的 通过体外实验观察兔骨髓基质干细胞(BMSCs)与改良复合磷酸钙骨水泥(BCPC)共培养的生物相容性及诱导成骨活性,探讨其可能的机制.方法 配制相同大小规格的BCPC及普通磷酸钙骨水泥(CPC)块,实验分为4组:空白对照组(不加载体)、普通CPC组、BCPC组、加BMP组(加BMP的BCPC).将各组材料与兔BMSCs复合培养,倒置显微镜下观察细胞生长情况,进行细胞计数,碱性磷酸酶(ALP)试剂盒检测细胞合成ALP活性变化,扫描电镜观察细胞在材料表面的生长及长入情况,real-time PCR检测成骨及成软骨相关基因mRNA表达情况并比较表达差别.结果 复合培养后倒置显微镜观察各组细胞与载体边缘接触良好,各组细胞增殖差异无统计学意义(P＞0.05);扫描电镜观察细胞在BCPC表面生长增殖良好,逐渐伸出伪足并长入材料孔隙;复合培养7 d后,BCPC组及加BMP组比CPC组和空白对照组表达更高的ALP活性,差异有统计学意义(P＜0.05);复合培养第10天,BCPC组及加BMP组分别与CPC组及空白对照组比较,其成骨及成软骨相关基因mRNA表达差异有统计学意义(P＜0.05).结论 配制的BCPC具有良好的生物相容性和一定的成骨诱导能力,其疏松的结构及更大的孔径适宜细胞长入材料内部.

Effect of modified composite calcium phosphate bone cement on osteoblast differentiation in vitro

Objective To investigate in vitro the biocompatibility of modified calcium phosphate bone cement(BCPC) and rabbit bone mesenchymal stem cells (BMSCs) as well as the effect of the composite on the growth and osteogenic differentiation of rabbit BMSCs. Methods The blocks of BCPC and ordinary calcium phosphate cement (CPC) were prepared in the same size. The experiment was conducted in 4 groups: ordinary CPC group, BCPC group, BCPC plus bone morphogenetic protein (BMP) group and blank control group.Rabbit BMSCs were co-cultured with the 4 vectors respectively. Cell growth was observed by inverted phase microscopy. Changes in the alkaline phosphatase(ALP) activity were detected by an ALP test kit. The BMSCs growth on the surface of the vectors was observed by scanning electron microscopy. Real-time PCR was used to measure the expressions of relative gene mRNA for osteogenesis and chondroblasts. Results There was no statistical difference in cell proliferation among the 4 groups( P ＞ 0.05 ). The BMSCs contacted well with the vector edges and grew well on the surface of the vectors. Scanning electron microscopy showed the pseudopodia extended from the cells into the pore of BCPC. Higher activity of ALP was detected in the BMP and BCPC groups than in the other 2 groups 7 days after co-culturing( P ＜ 0.05 ). On the 10th day after co-culturing, the expressions of relative gene mRNA for osteogenesis and chondroblasts were significantly higher in the BCPC and BMP groups than in the control group( P ＜ 0.05 ). Conclusions The BCPC has a good biocompatibility with BMSCs and can induce osteoblasts to a certain degree. The porous structure and large apertures of the vector enable cells to grow into its deep layers.