内源性骨髓间充质干细胞与骨折微环境中的相关趋化因子

背景：研究表明,骨髓间充质干细胞定向迁移依赖于损伤局部表达趋化因子与细胞表面相应受体的相互作用。然而,哪些趋化因子在介导骨髓间充质干细胞向骨折部位定向迁移过程中起关键作用,目前尚不清楚。目的：对内源性骨髓间充质干细胞进行示踪,观察其在骨修复中的作用;检测并筛选出骨折微环境中表达量高且与骨髓间充质干细胞趋化规律相关的因子。方法：建立C57BL/6小鼠荧光/普通骨髓嵌合体,利用嵌合体动物模型制造胫骨骨折模型,在不同时相点检测骨折部位组织绿色荧光蛋白阳性细胞占所有细胞的比例、来源于骨髓间充质干细胞的成骨细胞占全部成骨细胞的比例,判断来源于骨髓的骨髓间充质干细胞在骨折修复中的作用;利用免疫组化等方法检测骨折部位不同时相点趋化因子的蛋白表达水平。结果与结论：骨折局部绿色荧光蛋白阳性细胞占所有细胞比例在术后1,5,14 d分别为(3.011±0.911)%,(9.031±0.145)%,(12.064±0.145)%;来源于骨髓间充质干细胞的成骨细胞占全部成骨细胞的50%以上;骨折后各时相点微环境中基质细胞衍生因子1、集落刺激因子、肝细胞生长因子、单核细胞趋化蛋白1、间质金属蛋白酶9有不同程度的表达,粒细胞集落刺激因子无明显表达。基质细胞衍生因子1的表达量相对最高。经相关分析认为：基质细胞衍生因子1在骨折微环境中的表达与骨髓间充质干细胞趋化规律具有相关关系。结果表明骨髓内的骨髓间充质干细胞参与骨折修复并在其中起到了重要作用;基质细胞衍生因子1促进骨髓间充质干细胞的定向趋化并参与骨组织的修复。

Autologous bone marrow mesenchymal stem cells and related chemokines infracture microenvironment

BACKGROUND:The oriented migration of bone marrow mesenchymal stem cells may depend on the interaction between local chemotactic factors and cell surface receptors. However, which chemotactic factors may mediate the oriented migration of bone marrow mesenchymal stem cells towards the fracture site remains unclear.OBJECTIVE:To tag autologous bone marrow mesenchymal stem cells, evaluate its role in bone healing, and detect the highly expressed factors associated with migration of bone marrow mesenchymal stem cells in the microenvironment.METHODS:The fluorescence/chimeric C57BL/6 mouse models were established, then left shankbone fracture models were also produced. The percentages of green fluorescent protein positive cells to all cells at the fracture site and the percentage of osteoblasts differentiated from bone marrow mesenchymal stem cells to all the osteoblasts were detected at different time points. The role of bone marrow mesenchymal stem cells in the fracture repairing was evaluated. The levels of chemotactic factors protein expression at the fracture site in different time points were detected with immunohistochemistry technology.RESULTS AND CONCLUSION: The percentage of green fluorescent protein positive cells to all cells at the fracture site was (3.011±0.911)%, (9.031±0.145)%, (12.064±0.145)% at 1, 5, 14 days postoperatively; and osteoblasts differentiated from bone marrow mesenchymal stem cells accounted for 50% of all the osteoblasts. After fracture, the stromal cell derived factor-1, colony stimulating factor, hepatocyte growth factor, monocyte chemoattractant protein-1, and matrix metalloproteinases-9 were expressed to varying degrees in the microenvironment, while the expression of granulocyte colony-stimulating factor was negative. The expression of stromal cell derived factor-1 in the fracture microenvironment was the highest, mainly due to the migration of bone marrow mesenchymal stem cells. Experimental findings indicate that, autologous bone marrow mesenchymal stem cells participate in and play an important role in bone healing. The stromal cell derived factor-1 plays an important role in promoting bone marrow mesenchymal stem cells migration and promoting bone healing.