| With the leap in social change and the rapid development of the transportation industry, people are more and more high-energy injury, but more complex in patients with severe injuries, fracture type is also complex and varied, In clinical practice, bone defects and fracture healing is still plagued our problems, associated with nerve damage are more more difficult to treatment.ObjectivIn this study, through the establishment of denervation of tibial fracture model to explore the peripheral nerve on tibial fracture healing and the possible mechanisms for improving the neurological function to provide a theoretical basis for the promotion of fracture healing.MethodsChoosing Health 50 rats, weighing 250-300 g, males and female were randomly. Make the same rats two tibia as experiment group and control group, After the success of anesthesia, sterile conditions, take two lower limbs to do about 1cm inside the surgical incision, Appropriate exposure to the lower tibia, major surgery with a sharp scissors cut both sides of the tibia, Check bilateral tibia were completely transected, in order to maintain the stability of the fracture, both sides are so rigid internal fixation with Kirschner wire. Randomly selected with the side of the lower limbs at the same time in sterile conditions, cut off the femoral nerve and sciatic nerve, in order to prevent postoperative regeneration of connections, combined resection of two distal about 0.5cm, as the experimental side; On the other side to maintain neural integrity, as for the control side. After washing the wound with normal saline,1-0 silk suture muscle and skin, covered by sterile wound dressings. After all the experimental animals placed in a separate feeding the litter box to prevent the metal cage injury denervated side of limbs, and pay attention to incubation, for three consecutive days after intramuscular injection of penicillin 10000 units/kg body weight, three times/day, and Topical application of povidone-iodine disinfection of wounds the next day, to prevent wound infection. The experimental animals at various time points after 4,7,14,21,28 days were killed 5, two days and the previous week before the execution, and tetracycline hydrochloride (30mg/kg) by subcutaneous injection. Observed:Experimental animals were killed after the line of X ray camera to observe laboratory animals with bilateral changes in tibial bone healing, measuring and comparing the growth of callus; Experimental animals were sacrificed before the removal of the knee and ankle joints around the attachment of muscles and joint capsule to retain a complete tibia, visual observation of the growth of callus and texture. Fracture of the tibial stump, including callus, hematoma and periosteum were removed with light microscope examination, carried out histological analysis, observation of bone cell proliferation, differentiation, and bone calcification was conducted by fluorescence detection, observation deposition, and each group of data for statistical analysis and drawing conclusions.Results1,Imaging examination:Film X ray detection in the evaluation of bone callus, After 4 days and 1 week no significant difference between the two groups of callus, have no significant callus growth; The two groups have emerged after two weeks of high-density shadow in the experimental group more callus volume, density, compared with the control group is poor, and uneven; After 3 weeks,there more callus in experimental group as compared to contralateral,and low density in a great mess; a large number of experimental group after 4 weeks of callus growth, compared with the control group was prominent cortical bone, bone mineral density uneven.2,Histological examination under light microscope:Hematoma after four days the two groups are the main, only a small amount into a fibrous tissue, no significant difference between the two groups; 1 week after surgery, the experimental group a large number of fibrous tissue proliferation, fibrosis control group active in mesenchymal cells increased and visible part of the cartilage cells.The two groups 1 week after the results of the histological score: 0.6±0.42,1.1±0.42, no significant difference between the two groups (P> 0.05);After 2 weeks, new bone formation of the experimental group increased, but the sparse growth of the control group had more cortical bone formation, higher maturity, more compact, two histological score:1.4±0.42,2.2±0.57, difference between the two groups was statistically significant (P<0.05); 3 weeks after experimental cortical bone formation, low maturity, relatively sparse, narrow trabecular bone, the control group further increased cortical bone maturation and gradual integration of new bone connected pieces, arranged rules, wider trabecular bone, The results of two sets of ratings:2.1±0.42,3.4±0.42, difference between the two groups was statistically significant (P<0.05); 4 weeks after the experimental group over the growth of callus, which wre very immature and irregular arrangement, and the control group close to the normal structure of bone tissue in rats.The results of two sets of ratings:3.2±0.44,4.6±0.42, difference between the two groups was statistically significant (P<0.05).3,Tetracycline markers observed by fluorescence microscopy results:After 4 days and 1 week There were no clearly marked line, no significant difference between the two groups; 2 weeks after fracture, the experimental group was less sedimentary fluorescent substances, the normal nerve group was seen a large number of fluorescent material deposition.3 weeks after operation in control group have more fluorescein deposition, Division uneven deposition of material was lower than the experimental group, the distribution is wider, more densely arranged in neat; After 4 weeks, the test group no significant increase in fluorescent deposits,there is still a large number of deposition, the color deepened, branch-intensive and neat arrangement in control group.4,Immunohistochemical staining:after 4 days There were no positive expression;1 week callus in the experimental group shows little expression of CGRP-positive, were scattered punctate distribution of stain lighter;control callus tissue can see the expression of CGRP-positive, multi-focal distribution along the vessel, dyeing lighter; After 2 weeks of callus in the experimental group only very low levels of CGRP expression,in the control group had a large number of CGRP immunoreactive nerve fibers, and a gradual increase in staining was deepening; 3,4 weeks after, the experimental group was still very low expression levels of CGRP and in the control group there are more positive expression of CGRP, but more significantly after 2 weeks significantly reduced to near normal.Conclusions Peripheral nerve on fracture healing plays an important regulatory role, Experiment to prove that it not only affects the distribution of bone callus, growth speed and quality, but also can regulate osteoblast and osteoclast balance and promote deposition of calcium and phosphorus to accelerate the type of bone mineralization, bone callus maturity, so that bone trabecular reconstruction。Fracture healing is inseparable from the rich blood supply, some neuropeptides can regulate blood vessel activity by regulating blood vessel dilation and vascular permeability, thereby affecting the blood supply, accelerate the metabolism of bone fracture, affecting fracture healing, but also can contribute to fracture the regeneration of blood vessels to restore blood supply to meet the needs of a large number of fracture healing nutrients.neuropeptides can also promote the local soft-tissue healing, for the fracture healing of soft tissue to provide a good environment to accelerate fracture healing.
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