Study On Expression Of Bone Growth Factor Before And After Surgery For Infected Bone Defect

Background and Objective:In recent years,with the improvement of China’s economic strength and comprehensive national strength,the vigorous development of the transportation industry and construction industry,and the increase of human outdoor activities,complex and open injuries occur frequently.Infected bone defect is a severe complication of open fracture that usually results in destruction of bone tissue structure and prolonged infection,causing varying degrees of negative impact on the patient’s later life quality and mental health.In the treatment of infected bone defects,it is the most important to promote the healing of bone injury while resisting infection.At present,the clinical application of bone removal in the treatment of infected bone defects has achieved a certain effect.Based on the principle of osteogenesis by traction,which stimulates bone tissue and neurovascular regeneration through slow and continuous traction,thus promoting the healing of bone defects.Bone growth factor,hormone,reconstruction of perilesional blood supply and nerve regeneration are closely related to the healing of infected bone defects,of which bone growth factor plays a crucial role in bone regeneration,repair and reconstruction.The aim of this study was to investigate the expression of insulin-like growth factors-1（IGF-1）and basic fibroblast growth factor（b-FGF）in infected bone defects before and after surgery and their correlation with the healing of infected bone defects.Methods:Thirty-six male SD rats were selected to establish an infectious bone defect rat model by artificially creating a bone defect of about 4 mm in the tibia segment of rats and injecting aureus into the bone defect.After 2 weeks,rats are randomly divided into operation group and control group,with 18 rats in each group.The operation group underwent debridement and bone transport surgery.In the control group,debridment was performed without moving after the installation of the scaffold.X-ray film was taken 2 weeks after surgery,and H&E staining and Elisa were used at the 2^nd,3^rdand 4^thweeks to detect and analyze the healing of infected bone defects and the expressions of IGF-1 and b-FGF in the two groups.Results:Results:（1）Three days after operation,the wounds of 36 rats showed local redness and swelling,limited activity and viscous pus outflow.One week after operation,the vital signs of all rats were stable and free to move.（2）X-ray results showed that callus formation was less in the control group,and the gap between bone defects was still more obvious.Compared with the control group,in the bone defect area of the surgery group,a large number of high-density callus formation,bone bridge formation could be seen at both ends of the defect,and recanalization of the bone marrow cavity were observed.（3）HE staining results showed that:In the second week,the control group showed a large number of tightly arranged cords of fibrous connective tissue,with bone trabeculae of different sizes and irregular shapes.In the operation group,the fibrous tissue decreased,more osteoblasts were seen,and the bone trabecula tended to be dense.In the third week,chondroblast,mesenchymal cells,and a few new capillaries were observed in the control group.More mesenchymal cells and new capillaries were seen in the operation group,and the bone trabecular structure was dense.In the fourth week,osteoblasts were present in the control group.Osteoblasts and a small number of osteoclasts were distributed,showing more osteoid tissues.In the operation group,osteoblasts and osteoblasts were dense,and the trabeculae were surrounded by dense osteoblasts,showing a large amount of osteoid tissue.（4）Serological results showed that:IGF-1 expression in the operation group was significantly different from that in the control group in the second and third weeks（p<0.05）.At the same time,b-FGF expression in the operation group was significantly higher than that in the control group in the second week（p<0.05）.Conclusion:（1）The rat model of infected bone defect can be successfully established by injecting Staphylococcus aureus into the bone defect.（2）The increased expression of IGF-1 and b-FGF after surgery may play a key role in the repair of infectious bone defects.