论文部分内容阅读
目的 探讨骨形态发生蛋白 2(bone morphogenetic protein,BMP2)对趋化因子 12(chemokine C-X-C motif-ligand-12,CXCL12)表达调节及其在骨折修复过程中的意义.方法 构建 BMP2 敲除鼠 BMP2cKO/+和 BMP2cKO/cKO.免疫组化分析正常小鼠、BMP2cKO/+小鼠及 BMP2cKO/cKO小鼠胫骨骨折模型中骨内膜细胞 CXCL12的表达及其随时间的变化.实时定量 PCR(RT-qPCR)比较对照组与 BMP2cKO/+小鼠骨内膜细胞及其分化细胞CXCL12、骨钙蛋白、α-SMA 表达差异.结果 BMP2cKO/+和 BMP2cKO/cKO小鼠 BMP2 显著低于对照组.小鼠骨折修复过程中骨内膜细胞和成骨细胞 CXCL12 表达明显升高,且表达 CXCL12 细胞先增多再减少;BMP2cKO/+小鼠骨折修复过程中表达 CXCL12 的骨内膜细胞和成骨细胞逐渐增加.BMP2cKO/+小鼠分离的骨内膜细胞CXCL12 表达显著高于正常小鼠.在诱导分化的小鼠骨内膜细胞中添加 rhBMP2,CXCL12 的表达减少,骨钙蛋白和 α-SMA 表达显著增加.诱导分化的 BMP2cKO/cKO骨内膜细胞 CXCL12 表达显著高于正常小鼠,而骨钙蛋白的表达则显著降低.CXCL12 受体拮抗剂 AMD3100 处理诱导分化的 BMP2cKO/cKO骨内膜细胞,骨钙蛋白和α-SMA 表达显著增加.结论 骨折修复过程中,BMP2 下调 CXCL12 的表达有助于成骨细胞的分化从而促进骨折的修复.“,”Objective To investigate regulation mechanism of bone morphogenic protein 2 ( BMP2 ) on chemokine C-X-C motif-ligand-12 ( CXCL12 ) expression in the fracture repair and its clinical significance. Methods Knockout mice of BMP2 ( BMP2cKO/+and BMP2cKO/cKO) were constructed. Immunohistochemistry methods were used to analyze the cells with CXCL12 expression and the timely changes in the controlled, BMP2cKO/+and BMP2cKO/cKO mice bone fracture repair models. Real time-qPCR was used to compare the expression changes of CXCL12, osteocalcin and α-SMA gene in endosteal cells and differential endosteal cells isolated from the controlled, BMP2cKO/+and BMP2cKO/cKOmice. Results The expression of BMP2 was significantly lower in BMP2cKO/+and BMP2cKO/cKOmice than the controlled mice. CXCL12 was expressed in the endosteal cells and some osteocytes during mice fracture repair, and the cells with CXCL12 expression increased at the beginning and then decreased. The endosteal cells and osteocytes which expressed CXCL12 increased gradually in BMP2cKO/+mice. CXCL12 expression in endosteal cells isolated from BMP2cKO/+mice was higher than that cells from the controlled mice. In isolated endosteal cells, rhBMP2, while inducing osteoblastic differentiation, stimulated expression of osteocalcin and α-SMA that was coupled with a decrease of CXCL12 expression significantly. In isolated BMP2cKO/cKOendosteal cells, high CXCL12 expression and low osteocalcin expression were observed. In isolated BMP2cKO/cKOendosteal cells with AMD3100 ( an antagonist of CXCL12 receptor ) treatment, osteocalcin and α-SMA expression increased. Conclusions In fracture repair process, BMP2 leads to the downregulation of CXCL12 expression that would facilitate endosteal cells differentiating into osteoblasts and promote fracture healing.