| The fracture is the most common disease in clinical orthopediac works,the research on its healing process has always been the focus. People have tended to recover its mechanism and inferior relations by various means and then used it to clinical works to lower the unhealing ratio.There are so many fields referring to fracture healing,from macroscope to microscope,from molecular biology to biomechanics,from growth factors to histoengineering.The bone formation and growth is a complicated process,which comprise of cells,molecular and biochemical metabolism.There are two method on the bone growth :intramembrane ossification and endochondral ossification. The intramembrane ossification appears on the bonesurface when the osteoblast calcifies into osteoid matrix in the collagen framework,and is followed by the primitive mesenchymal cellular differentiation;The endochondral ossification appears at growth plates(which appears in the cartilage mass among embryo and fetus period) and fracture tip when osteoblast develop into osteoid on the cartilage framework.With the revealing of the bone differentiation and introduction of the molecular biology,it will help us to know the fracture healing mechanism better. The bone development and healing are controlled by many growth factors which can accelerate its healing.It has been the focus on the effect of platelet-rich plasma to fracture healing.Because there are some growth factors which take there effects in fracture healing process by co-operation and mutual acceleration.the most important growth factor is PDGF,which appear earlist and accelerate the fission and production of the undifferented cells,as well as IGF and BMP.Until now ,there are a few reports about the effect on fracturehealing ,but seldom about limb fracture .we tende to explain the effect of platelet-rich plasma on fracture healing by hybridization in situ,immunobiochemistry and biomechanics.Part 1 The expression of PDGF in fracture healingObjection:By investigate the expression of PDGF ,we studied the effect of platelet-rich plasma on fracture healing and provided a theoritic background to its clinical application.Method: To making of animal fractural model,we selected 24 New Zealand rabbits and divided them into 4 groups randomly(blank group,serum-control group,group with platelet concentrated liquid ,group with bone graft and platelet concentrated liquid), then made the fracture model. Before the operation , 6ml blood was drawn out from its artery and followed by low and high speed centrifigation, then the 0.5ml white blood plate was purified . Among the model group, we incided the ulnar periosteum along the muscular interspace after abdominal injectional anesthesia with sodium pentobarbital(0.5ml/kg).then cut off the ulnar, fixed with steel plate and screw, we placed agelatin sponge which absorbed the purifided platelet concentrated liquid by it.Amonge the group with bone graft,the purifided platelet concentrated liquid was directly injected into the grafted bone which was made use of the right illium. We detected the fracture position after The rabbits were killed at 2nd,4th,8th weeks separately,then investigate the expression of PDGF by analysis with hybridization in situ,immunohistochemistry .Result: â‘ By gross observation, there is mostly fibery conection in the blank group and serum-control group.around the fracture tip ,there is much granulation tissue and little callus.however, the adverse result presented in the group with platelet concentrated liquid and group with bone graft and platelet concentrated liquid . â‘¡By hybridization in situ the PDGF expression in platelet-rich plasma group is strongest,the next is the group with bone graft and platelet concentrated liquid,there is little expression in other two groups.â‘¢ By immunohistobiochemistry, thePDGF expression in platelet-rich plasma group is the stronger than other groups, the blank group is lest. Conclusion: There are many growth factors in the plasma rich in platelet,which play...
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