| Objective:To evaluate the effect of human umbilical cord mesenchymal stem cells(hUMSCs)and hyaluronic acid/BMP-2(bone morphogenetic protein)composite on bone defect repair.Methods:Fifteen male New Zealand white rabbits with similar body weight were randomly divided into blank group and control group and experimental group to establish models of right radial bone defect in 15 male New Zealand white rabbits which were purchased from Medical Center of Xi'an Jiaotong University.In the blank group,the soft tissue and skin were sutured layer by layer without any other treatment.In the control group,two ends of radius defect with silicone tube,each of them was inserted about 3mm,and hyaluronic acid 1ml was injected into the silicone tube with syringe,and the soft tissue and skin were sutured layer by layer.The experimental group,two ends of radius defect with silicone tube,each of them was inserted about 3mm,and the human umbilical cord mesenchymal stem cells and hyaluronic acid/BMP-2 composite material was implanted into the silicone tube at 1ml(containing hUMSCs1x10~7 BMP-20.5 mg/g),and the soft tissue and skin were sutured layer by layer.The treatment of the three groups was the same after operation,without restriction of movement.X-ray films were taken at 2th and 4th and 8thweeks after operation to observe the healing of radius in each group.At the 8th week,the animals were killed after X-ray examination.Bone tissues of radius defect and bilateral 1cm were stained with HE staining,tetracycline fluorescence staining and bone biomechanics examination.Results:X-ray examination showed that no high-density images were found in bone defect area of each group at 2th weeks after operation.At 4th weeks after operation,there were conical high-density shadows at both ends of the bone defect area in the experimental group,and the tip pointed to the center of the defect,but no high-density area was found in the blank group and the control group.At 8th weeks after operation,the bone defect area in the experimental group was completely high-density and the outline was clear.The center of bone defect in blank group and control group was still low density bone defect area.Conical high density shadow could be seen at both ends of the bone defect center.The blank control group had normal structure of bone tissue,ordered arrangement of bone cells,and no inflammation.Necrosis,etc.In the hyaluronic acid control group,a large number of inflammatory cells were infiltrated and some bone tissues were necrosed in the bone defect,indicating that the repair effect was poor.In the experimental group,there were more callus formation,more collagen fibers,new bone trabeculae and blood vessels in the repair area of bone defect,and a few lamellar structures could be seen near the broken end.Under the microscope of tetracycline fluorescence staining,it can be seen that the fluorescence distribution of blank group and stem cell group is more,the intensity is stronger,and the group of sodium hyaluronate is relatively weak.The maximum stress was 896.5±80.3N/mm~2 in the blank control group,915.4±90.8N/mm~2in the control group and 1105.8±92.7 N/mm~2in the experimental group.Conclusion:The composite of human umbilical cord mesenchymal stem cells and hyaluronic acid/BMP-2 was implanted directly into the fresh fracture site of rabbits,which could promote the early repair of rabbit bone defect. |
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