The Study Of SDF-1?/CXCR4 Signal Pathway To Promote Bone Defect Regeneration By The Mechanical Stimulation

Objective: The research group has found and confirmed that bone stress stimulation can promote fracture healing and tissue engineering bone regeneration,but its specific mechanism is still unclear.The purpose of this study is to observe the change of SDF-1?/CXCR4 signaling pathway during the process of bone stress stimulation,and to further understand its mechanism.Methods: A total of 72 New Zealand rabbits were selected to drill a 8mm round single cortical bone defect model at the proximal end of the right tibia.They were randomly divided into 3 groups.In group A(n=24),the bone defect was transplanted into the deproteinized bone(blank control group).In group B(n=24),on the basis of group A was treated with stress stimulation(percussion stress group).In group C(n=24),on the basis of group B was intraperitoneally injected with AMD3100 solution(signal pathway blockage group).Group C was given an intraperitoneal injection of PBS solution of AMD3100(concentration of 0.1mg/ml)on the day after the operation,with a dose of 5ml/kg,1 times a day,while in groups A and B,the same PBS solution was injected with the group C.In the other B and C two groups,the bone stress irritation instrument was given to the heel of the rabbit on the eighth day after the operation.The percussion parameters were as follows: 1 times every 2 days of axis to stress percussion,each time 30 min,the stress size was 15 N,the frequency was 1Hz,the percussion time was 5s,and the interval time 3s.All rabbits were fixed by plaster cast after operation and percussion.X-ray films were taken at 2,4,8 and 12 weeks after operation,and Lane-Sandhu bone healing score was used to evaluate the healing of bone defects.After the animals were killed at various time points,gross specimens were observed and histological staining was used to observe the new bone tissue,DPB degradation and related molecular markers.Conclusion: The process of bone defect regeneration is regulated by SDF-1 alpha /CXCR4 axis.By tapping axial stress stimulation,the expression of SDF-1 alpha in the damaged tissue of the fracture area is up-regulated,thus more BMSCs is chemosed to the bone defect area and the process of bone regeneration is repaired.