Exogenous Nerve Growth Factor And Fracture Healing Correlation Analysis

Background:Fractures are common and frequently occurring in clinical. With modern transportation and the rapid development of transport. Bone damage more and more common, the injury is also growing increasingly more complex. Patients with fractures, due to the long duration of time, and more associated with limb dysfunction, serious mental pressure and economic pressure on patients and the entire families.Mechanism of fracture healing is very complex, it involves the biochemistry, cell biology, biomechanics, endocrinology, and other mineralogical and cross-professional disciplines. Currently, the most studied mainly in three aspects. First, molecular biology, mainly refers to the transforming growth factor-β (TGF-β), fibroblast growth factor (FGF), insulin growth factor (IGF), platelet derived growth factor (PDGF) and vascular endothelial growth factor (VEGF) and so on. Second, the study of physical factors, including electromagnetic, ultrasonic, etc. Third, tissue engineering, mainly constructed by in vitro or in vivo living tissue to replace the non-autologous tissue transplantation and artificial life, material substitution therapy, implanted after completion of tissue regeneration, healing, involved in metabolism and various physiological function, and ultimately support the weight of the skeletal system and load the basic physiological function of exercise load. However, fracture healing due to so many factors, there is another injury site and individual differences, delayed union and nonunion fractures also occur. How to reduce heterotopic ossification nonunion, and promote fracture healing clinical orthopedic surgeons as problems to be solved. In clinical work, we found that patients with traumatic brain injury in fracture callus growth speed, quantity, even in the muscle tissue can also be found in the phenomenon of heterotopic ossification, fracture healing significantly faster than patients without head injury. So, NGF and fracture healing is a correlation?This study was designed to study nerve growth factor to promote the role of fracture healing, through the establishment of rabbit fracture model for nerve growth factor associated with fracture healing and provide experimental basis.To give the nerve growth factor, through the detection of changes in different time periods indicators to understand whether NGF can promote healing. In order to guide clinical treatment of osteoporosis, delayed union, malunion, nonunion, and heterotopic ossification provides new methods and ideas.Objective:The project through the establishment of rabbit fracture model for nerve growth factor associated with fracture healing experimental basis; After the granting of nerve growth factor, at different times by the detection of changes in relevant indicators to understand whether NGF can promote healing.If further evidence of nerve growth factor in the role of osteoblast activity, compared with the clinical fracture healing and reduce the occurrence of heterotopic ossification nonunion provide effective and safe treatment.Methods:Standard experiment used24New Zealand white rabbits of either sex, weighing3000-3500g. After the success of the anesthetized rabbits, broken tibia1/3, the platform front row inserted intramedullary Kirschner wire fixation, postoperative cast immobilization. Anti-inflammatory for5-7days after intramuscular injection of penicillin to prevent infection.After the modeling, with grade1-24, completely randomized design is divided into A, B, C, D four groups of six. A test group of nerve growth factor in the treatment group, positive control group B of BMP-2group, the third group C of NGF+BMP-2group, negative control group, group D, for the saline injection group. Group A starting from postoperative3days, A tibia fracture at the end was injected NGF18ug/2kg, once a day for2weeks; B group patients at the fracture site in the BMP-2implanted gelatin sponge; C group of the fracture during surgery Gelatin sponge implanted BMP-2, and3days after operation started at the tibial fracture injection NGF18ug/2kg, once a day for2weeks; D group was injected with saline in the same part of the same dose, a total of2weeks. Each group were14,21and28days after surgery, the line X-ray examination, bone mineral density and osteocalcin determination, RT-PCR, histological observation of bone in the Ⅰ expression of collagen.Results:1. General samples were X-chip check:after each time point A, B, C group gradually increased callus growth, cell proliferation significantly, the early formation of a large number of trabecular bone, are superior to D group.2. Bone mineral density and osteocalcin determination:with time,the callus density and osteoclcin levels gradually increased, and the NGF group, BMP-2group and NGF+BMP-2group was significantly higher than the saline group (P<0.05). NGF group, BMP-2group and NGF+BMP-2group was not statistically significant (P>0.05).3. Histological observation:14days after operation, NGF group, BMP-2group and NGF+BMP-2group visible in the fracture fragments at the cartilage tissue and a small amount of osteoid tissue with capillaries and mesenchymal interstitial cells grew into the saline group mainly of fibrous tissue proliferation, callus small and disorgnized, and the bone tissue and cartilage was significantly less than the previous three groups.21days after operation, NGF group, BMP-2group and NGF+BMP-2group osteoblast cells proliferation, showing interwoven reticular trabecular bone, with bone marrow and bone tissue visible on the surface of osteoblast, NS group of cartilage and a small amout of bone tissue, cartilage tissue formation of bone marrow cavity, mature trabecular bone.28days after operation, NGF group, BMP-2group and NGF+BMP-2of trabecular bone are basically ripe, arranged along the long axis of the lamellar structure is more obvious, the callus shaping reconstuction almost entirely, and there are a large number of active the presence of osteoblasts. Saline group shows a more mature trabecular bone, bone mineralization is not complete, the local area visible remnants of the cartilage.4. RT-PCR and the I collagen expression:A, B and C group mRNA and I collagen expression were higher than those D group.Conclusion:1. An experiment rabbit after injection of NGF fracture callus growth rate, bone mineral density, osteocalin values significantly higher than the saline control group, to promote fracture healing.2. NGF have a synergistic effect with BMP-2to participate in the regeneration of bone, can promote fracrure healing.