骨髓间充质干细胞对创伤性骨折愈合的促进作用

Promotion of bone fracture healing by bone marrow mesenchymal stem cells

背景:近年来随着干细胞培养、分离等技术的发展使骨折不愈合的治疗有了更多的选择。目的:探讨骨髓间充质干细胞在大鼠创伤性骨折愈合过程中的促进作用,以及对内源骨髓间充质干细胞迁移能力的影响。方法:48只Wistar大鼠,随机分为实验组、对照组各24只。所有大鼠均建立股骨骨折模型。另采用贴壁筛选法分离制备健康大鼠骨髓间充质干细胞,通过尾静脉注入实验组大鼠,对照组注入等体积生理盐水。分别于2,3,4,8,12周提取两组大鼠股骨骨髓间充质干细胞,用荧光定量RT-qP CR方法检测细胞中Ⅰ型胶原蛋白和CD44的表达,采用Transwell法测定骨髓间充质干细胞迁移情况,并用免疫组化方法检测骨痂处神经生长因子表达。结果与结论:(1)第2,3,4周,实验组大鼠骨髓间充质干细胞Ⅰ型胶原蛋白、CD44 mR NA表达明显高于对照组,差异有显著性意义(P<0.05);(2)第2,3周,骨髓间充质干细胞迁移能力明显高于对照组(P<0.05);(3)第3,4,8,12周,实验组骨痂处神经生长因子表达高于对照组(P<0.05);(4)结果表明,外源骨髓间充质干细胞植入股骨骨折大鼠体内可使内源骨髓间充质干细胞的体外迁移能力及骨折部位神经生长因子表达增强,从而促进大鼠骨折愈合。

BACKGROUND：In recent years, the development of stem cel culture and isolation technologies provides new therapeutic choices for fracture healing. OBJECTIVE：To investigate the effect of exogenous bone marrow mesenchymal stem cel s on bone fracture healing in traumatic fracture rats and on the migration ability of endogenous bone marrow mesenchymal stem cel s. METHODS：Femoral fracture models were made in 48 Wistar rats and then randomized into experimental group and control group （n=24/group）. Bone marrow mesenchymal stem cel s from another healthy rats were isolated using adherent method and then injected into the rats via the tail vein in the experimental group. Rats in the control group were given the same volume of normal saline. At 2, 3, 4, 8, 12 weeks after injection, we extracted bone marrow mesenchymal stem cel s from the femur of rats in the two groups. RT-qPCR was used to detect expression levels of type I col agen and CD44. Transwel method was used to detect cel migration ability. Immunohistochemitry method was employed to detect expression of nerve growth factors in the cal us. RESULTS AND CONCLUSION：mRNA levels of type I col agen and CD44 in rat bone marrow mesenchymal stem cel s were significantly higher in the experimental group than the control group at 2, 3 and 4 weeks after injection （P〈0.05）. Compared with the control group, the higher migration ability of bone marrow mesenchymal stem cel s was found in the experimental group at 2 and 3 weeks after injection （P〈0.05） as wel as the higher expression of nerve growth factor in the cal us in the experimental group at 3, 4, 8, 12 weeks after injection. Al these findings suggest that exogenous bone marrow mesenchymal stem cel s can improve the migration ability of endogenous bone marrow mesenchymal stem cel s and the expression of nerve growth factor in the cal us in rats with femoral fracture, thereby promoting fracture healing in rats.