骨髓间充质干细胞定向趋化及骨修复中基质细胞衍生因子1的作用

背景：骨折愈合与聚集在骨折端的骨髓间充质干细胞的数量及功能密切相关,基质细胞衍生因子1可增强骨髓间充质干细胞的趋化功能。 目的：采用携带绿色荧光蛋白转基因骨髓间充质干细胞的骨髓嵌合体小鼠,制作左胫骨骨折模型,观察基质细胞衍生因子1对骨髓间充质细胞定向迁移的影响及其骨折修复中的作用,并初步探讨其作用机制。 方法：利用密度梯度离心法从携带绿色荧光蛋白转基因小鼠C57BL的骨髓内分离培养出携带绿色荧光蛋白的骨髓间充质干细胞;将经X射线照射后携带绿色荧光蛋白转基因的骨髓间充质干细胞与雄性小鼠的骨髓非贴壁细胞联合移植,最后建立起稳定的骨髓嵌合型小鼠模型,再建立左胫骨骨折模型。建模后分别用基质细胞衍生因子1和基质细胞衍生因子1抗体干预,并设置对照组。 结果与结论：建模后第1,3,7,14天各相应时相点骨折端的骨髓间充质干细胞数量,建模后第14,21天各相应时相点的骨痂量,建模后第28天抗折力,均为基质细胞衍生因子1组>对照组>基质细胞衍生因子1抗体组(P < 0.05);在建模后第28天基质细胞衍生因子1组骨痂量减少(P < 0.05),骨小梁融合成片,部分骨髓腔再通,对照组和基质细胞衍生因子1抗体组髓腔未通。证实,基质细胞衍生因子1 可促进骨髓间充质干细胞向骨折端迁移,具有促进骨折愈合的作用。

Effect of stromal cell derived factor-1 on migration of bone marrow mesenchymal stem cells and bone healing

BACKGROUND:The number and function of bone marrow mesenchymal stem cells in the fracture end are closely correlated with fracture healing. Stromal cell derived factor-1 can promote the chemotactic functions of bone marrow msenchymal stem cells. OBJECTIVE:To establish the left tibia fracture model by using the chimeric mice with stably expressing green fluorescence protein positive bone marrow mesenchymal stem cells, in order to evaluate the protective effect of stromal cell derived factor-1 on the migration of bone marrow mesenchymal stem cells and bone healing, and to explore the mechanism. METHODS:Green fluorescence protein positive bone marrow mesenchymal stem cells were harvested from bone marrow of green fluorescence protein transgenic C57BL mice by density gradient centrifugation method. The green fluorescence protein transgenic bone marrow mesenchymal stem cells combined with the non-adherent bone marrow cells in the male mice were transplanted after X-ray irradiation for establishing the chimeric mice model. After chimeric mice were established, left tibia fracture was made and induced with stromal cell derived factor-1 and stromal cell derived factor-1 antibody, and the control group was set. RESULTS AND CONCLUSION:The amount of bone marrow mesenchymal stem cells in stromal cell derived factor-1 group was higher than that in the control group and anti-stromal cell derived factor-1 group at 1, 3, 7 and 14 days after modeling (P < 0.05); the sum of callus in stromal cell derived factor-1 group were greater than that in the control group and anti-stromal cell derived factor-1 group at 14 and 21 days after modeling (P < 0.05); the average peak deformation of the fracture-healing site in the stromal cell derived factor-1 group at 28 days after modeling was greater than that in the control group and anti-stromal cell derived factor-1 group (P < 0.05); all the indicators above in the control group were greater than those in the anti-stromal cell derived factor-1 group. At 28 days after modeling in the stromal cell derived factor-1 group, the sum of callus was decreased (P < 0.05), the trabecular was integrated into the film and part of the marrow cavity was recanalized. The medullary cavity in the control group and anti-stromal cell derived factor-1 group was not recanalized. Stromal cell derived factor-1 can promote bone marrow mesenchymal stem cells to migrate into the fracture site and can accelerate fracture healing.