The Effects Of Stromal Cell Derived Factor-1 On Migration Of BMSCs And Bone Healing

Objective To explore the roles of Stromal cell derived-1 on migration of BMSCs and bone healing,to provide evidences for regulating the migration of BMSCs in the future.Methods (1)GFP positive BMSCs were harvested from bone marrow of GFP transgenic C57 mice by density centrifugation and identified through osteoblastic and adipogenic induction,the cells were tested CD44 and CD34 by flow cytometry.(2)1000 male GFP positive BMSCs and 1×106 cells from bone marrow those can not adhere were injected into female C57 mice of 4-week-old through tail vein after 10 Gy X ray irradiation to establish chimeric mice models.The ratio of GFP positive cells in bone marrow were detected by LSCM.(3)After chimeric mice were established, left tibia fracture were made in 135 chimeric mice and were devided into three groups randomly: A group mice were dealed with ECM, B group:100ng/ml SDF-1+ECM; C group: 2ug/ml anti-SDF-1+ECM, the volume of each injection is 0.1ml.The amount of BMSCs at the 1d,3d,7d,14d were detected by LSCM;The sum of callus were measured with radiography at the 14d,21d,28d;and the bone biomechanics were tested at the 28d post fracture.Results (1)GFP positive BMSCs grew as clony-like manner, expressed calcium deposition after induction by osteoblastic culture medium and formed fat droplets in adipogenic culture medium.(2)8 weeks later, the BMSCs were transplanted successfully into bone marrow, The ratio of GFP-positive cells in bone marrow cells was 3.124±0.10%. (3)The amount of BMSCs were in B group higher than those in A group and C group at the 1th,3th,7th,14th day after operation(P<0.05);the sum of callus in B group were greater than those in A group and C group at the 14th, 21th day after operation(P<0.05), and the sum of callus in A group were greater than those C group (P<0.05). the sum of callus in B group were smaller than those in A group and C group at the 28th day after operation(P<0.05),and were greater in A group than those in C group(P<0.05);The average peak deformation of the fracture-healing site in the B group at the 28th day were greater than those in A group and C group(P<0.05),the average peak deformation were greater in A group than those in C group(P<0.05).Conclusion (1)GFP positive BMSCs can be harvested from bone marrow of GFP transgenic mice C57 by density centrifugation. (2) It can establish chimeric mice models successfully by transplanting GFP positive BMSCs with cells from bone marrow that can not adhere into C57 mice. (3)SDF-1 can promote BMSCs migrate to the fracture site,and can accelerate fracture healing as well.