| Objective: TO Observed the Expression of nerve growth factor (NGF)receptor TrkA In simple fractures and ischemia associated with fracture, revealthe impact of of T r k A the expression change on fracture healing. Theconventional wisdom is that ischemia on fracture healing fractures caused bythe reduced supply of nutrients, In the past, More geared to Solid fixation andgood blood supply to observe fracture healing process at clinical, At present,growing number of scholars began to pay attention to the study from themicroscopic. Because axillary artery has the rich vascular network in theshoulder around, after the axillary artery was Ligated, limb of the bloodsupply can always be compensated through the collateral circulation network,Limbs can still survive. Foreign scholars Grills proved the NGFR promotefracture healing, and which the TRKA already been found in all boneformation like cells. But the studies on relationship between the TRKAexpression changes and the fracture healing have reported very few. In thisstudy, by the establishment of animal models for fractures with vascular injury,and observations the expression of TrkA and its influence on fracture healingin ischemia associated with fractures and simple fractures, Provides atheoretical basis for clinical treatment, Improve the Specific mechanisms thataffect fracture healing when fracture with injury, and to maximize the repair ofcomplex injuries of the limbs.Methods: Select56healthy SD big mouse, body weight300-350g, male orfemale, divide them into the experimental group and comparison group byrandom choice of body weight serial number, each group of28. After beinganaesthetized by abdomen injection of chloral hydrate, apply Medial obliqueincision in the left humerus. Cut the skin and subcutaneous muscle, exposedupper section of the humerus. Experimental group snapped humerus with Rongeur in the middle section of the humerus and ligate the trunk of theaxillary artery since the beginning of the axillary artery, The control groupsimply cut the exposed humerus, the artery not treated. The two sets offractures were fixed within a5ml syringe needle. Respectively, after surgery,1day,3days,5days,7days,14days,21days,28days, drawn observed TrkAexpression by immunohistochemical method, the data obtained werestatistically analyzed. And take the humeral X-ray at2,3and4weeks aftersurgery, observed of callus growth and fracture healing.And formorphological examination, the content of cellular components in thedetection of bone callus.Results: Two groups of animals were sacrificed at the stipulated time,drawing. And take the humeral X-ray at2,3and4weeks after surgery. Theexperimental animals were shooting limb X-ray film after the success ofanesthesia, the results show: Experimental group at2weeks only a smallamount of callus, fracture line is clear, while the control group began arelatively large number of callus, fracture line is more obscure;3weeks, callusvolume of the experimental group than the control group, but the calluscompared with the loose, no obvious law；Experimental group at4weekscallus growth is slow, uneven density and osteoporosis, the fracture line is stillclear, the control group showed callus density is uniform, the appropriateamount of callus, closely arranged, the fracture line has been blurred.Specimens Morphological observations under the light microscope,Inflammatory changes of the control group was significantly higher than theexperimental group after1week surgery,After two weeks, trabecular bone ofthe control group began to increase the activity of osteoblasts and osteoclastsat the same time, the callus around to see more new bone and cartilage tissue.Less osteoid tissue of the experimental group after3weeks, low osteoblastproliferation. The control group endochondral ossification. Control grouphas more bone island compared with the experimental group after4weeks.Immunohistochemical results showed: With TRKA positive grayscale integralof said results,1day after surgery, Experimental group(24.52±1.46), Control group(30.46±1.94), Statistics Significant difference(P<0.01);3days aftersurgery, Experimental group(45.08±1.48), Control group(56.05±1.66),Statistics Significant difference(P<0.01);5days after surgery, Experimentalgroup(72.37±1.94), Control group(82.53±1.47), Statistics Significantdifference (P<0.01);1week after surgery, Experimental group(94.65±2.28),Control group(105.43±3.29), Statistics Significant difference(P<0.01);2weeks after surgery, Experimental group(111.02±1.72), Control group(140.23±1.38), Statistics Significant difference(P<0.01).3weeks after surgery,Experimental group(103.93±2.41),Control group(108.96±1.69), StatisticsSignificant difference(P<0.01).3weeks after surgery, Experimental group(29.71±1.14), Control group(44.21±3.55), Statistics Significant difference(P<0.01).Conclusion: The experimental results show that(1)Fracture healing for theclose relationship with peripheral blood. Ischemia inhibit the activation of thenerve growth factor on fracture, The expression of TrkA decreased, Bone cellactivity is reduced, Influence on fracture healing process in the repair andreconstruction.(2) In the process of fracture healing fractures with vascularinjury patients the TRKA participation is extremely important role inpromoting fracture repair and regeneration. |
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