BMSCs膜受体CXCR4和CXCR7表达及其在骨创伤修复中的作用

Expression of CXCR4 and CXCR7 receptors in bone marrow mesenchymal stem cells and role of these receptors in bone repair

目的 探讨BMSCs膜表面受体CXCR4和CXCR7的表达及其在BMSCs迁移中的作用,为骨创伤修复提供理论依据.方法 选择C57BL/6小鼠经贴壁法培养获得第2代BMSCs,免疫荧光染色法和流式细胞技术检测BMSCs膜表面受体CXCR4和CXCR7的表达.趋化因子CXCL12诱导BMSCs迁移实验分为对照组（无血清培养基诱导BMSCs迁移）、CXCL12组（含CXCL12无血清培养基诱导BMSCs迁移）和CXCR4阻断组（含CXCL12无血清培养基诱导阻断膜受体CXCR4后BMSCs迁移）,统计BMSCs迁移数量,观察CXCR4和CXCR7趋化BMSCs迁移的作用.采用Western blot检测阻断膜表面受体CXCR4后CXCR7蛋白的表达.结果 免疫荧光结果显示大量BMSCs膜表面表达CXCR4和CXCR7.流式细胞仪检测结果显示BMSCs膜表面分子CXCR4的阳性率为96.4％,CXCR7的阳性率为97.3％.细胞迁移结果显示,CXCL12组BMSCs迁移量最高,CXCR4阻断组BMSCs迁移量显著低于CXCL12组但迁移量仍高于对照组（P＜0.01）,而阻断XCCR4后CXCR7蛋白表达升高.结论 CXCR4和CXCR7受体均表达于BMSCs膜表面,在CXCL12调节BMSCs迁移至骨创伤创面过程中CXCR4发挥主要作用.

Objective To investigate the function of CXCR4 and CXCR7 receptors expressed in bone marrow mesenchymal stem cells （BMSCs） membrane surface in process of cell migration,in order to provide a theoretical basis for bone trauma repair.Methods C57BL/6 mice were selected to collect BMSCs of second passage after using the adherence culture method.Expressions of CXCR4 and CXCR7 receptors on BMSCs membrane surface were detected using immunofluorescent staining and flow cytometry.In CXCL12-induced chemotaxis of BMSCs,the assay was divided into control group （cells were seeded in serum-free medium）,CXCL12 group and （cells were seeded in serum-free medium containing CXCL12）,and CXCR4-blocked group （cells were seeded in serum-free medium containing CXCL12 after the blockade of CXCR4）.Migration of BMSCs was qualified and used to determine the chemotaxis role of CXCR4 and CXCR7.After the blockade of CXCR4,expression of CXCR7 was detected using the Western blot method.Results lmmunofluorescence showed overexpressions of CXCR4 and CXCR7 receptors on BMSCs membrane surface.Flow cytometry showed the positive rate of CXCR4 and CXCR7 on BMSCs membrane surface was 96.4% and 97.3% respectively.Cell migration assay showed amount of MBSCs migration was the highest in CXCL12 group,relative higher in CXCR4-blocked group and the lowest in control group （P 〈 0.01）.In CXCR4-blocked group,expression of CXCR7 increased.Conclusion CXCR4 and CXCR7 Receptors are expressed in BMSCs membrane surface,but CXCR4 play the major role in CXCL12-induced BMSCs migration to traumatic bone wounds.