Expression Of PDGF,OPG And RANKL In The Healing Process Of Mandibular Fracture

Background: With the development of gene technology, it became popular that using molecular biological methods to research the healing process of bony fracture.In recent years, the healing process of bone fracture has been recongnized deeply from the cellular biology to the molecular biology because of the gene technical development and application. More and more growth factors in the fracture site have been discovered, which can promote healing of fracture.The growth factors include fibroblast growth factors(FGFs), transforming growth factor-β(TGF-β), platelet-derived growth factor (PDGF), bone morphogenetic proteins(BMPs) et al. Although the growth factors in mandibular organize and blood plasma is very tiny, they have play an important role in the bone fracture healing process including regulating the cell division, quality of base material to synthesize and divide with organization. Therefore, the growthfactors repair the function in the process research to have already been subjected to the value increasingly in the bone fracture.Researchs have already made the very big progress currently on the research of growthfactors, particularly platelet-derived growth factor, osteoprotegerin, Receptor activator of NF-KB ligand, which have all the important research meanings. Scientists have already proved now, the PDGF matches to the important function to the bone fracture more,and it can stimulate the DNA of the periosteum OB, osteogenitor cell, and OB to synthesize and the caryocinesia of the cell.The PDGF not only can promote the increment and differentiations of the cell, but also can promote the OB synthesize the collagen, by stimulating the collagenoblast to synthesize the gum original and extracellular matrix to promote the bone fracture healing, and also can cause the gum wait the extracellular matrix to sink to accumulate at first. Scientists study to confirm that the OPG rises to decide the function in maintain the bone stability, that can regulate the OB the hyperplasy and the activity, by building up the OPG transgenic animal pattern and OPG to the function occurrence of the bone fracture healing is in the wound part tissues. The output RANKL of OB combines with the RANK acceptor of the OC ex-body cell surface the exertive function, dividing into the OC of have the function activity. On the one hand the OPG that OB secreted is the RANKL Competing receptor, on the other hand, it combines the RANKL and repress the OC bone absorption.Thus attain the bone fracture repair recovery and the dynamic equilibrium of the bone fracture plasticses. Purpose:To study the expression of OPG and RANKL in the different stages of mandibular fracture healing process and analyze the relationship between OPG, RANKL and fractural healing in the animal experiment. To research the functional effect of PDGF for osteoblast and to discuss the mechanism of PDGF to OPG, RANKL in the signal transmission of bony healing through cellular culture. Method:There has been the research confirmation that the platelet-derived growth factor can promote to the healing of the bone fracture in the animal body, but the research of the platelet-derived growth factor developing the function of the osteoblast in vitro is less, In the animal body, the progress of bone fracture healing is accommodated by OPG and RANKL, but the expression in the mandibular fracture animal model and the indication to osteoblast in vitro, are reporting a less currently.This experiment designed a kind of new mandible animal model of fracture,observed the healing of mandibular fracture at different time,and the immunohistochemical expressions of OPG and RANKL in the osteoblast and osteoclast.We cultured primarily osteoblast in Vitro, induced it by anti-rabbit PDGF and OPG,observed the growth,differentiation,mineralization of obsteoblast, investigated the reverse transcriptase reaction and immunohistochemistry expression of OPG.. Result:The RANKL mainly expressed in the osteoclast after bone fracture,compared the showing the predominance difference with the osteoclast. PDGF can repress the growth, propagation, maturity, mineralization and expression of the OPG mRNA of the osteoblas having the marked differences comparing with osteoblast. The anti-rabbit PDGF represses the growth propagation, differentiation, mineralization and the expression in OPG mRNA of the osteoblast showing the conspicuous differences comparing with osteoclast. Conclusion:Among the healing of the fracture of mandibule, the expression was manifest in the organizes of bone and soft tissue, especially in the osteoblast. The OPG matches the bone in the process formation to expect to have the expression of predominanceamong the healing of mandibular fracture. The osteoclast expressed remarkably in the RANKL among the anaphase of mandibular fracture.regulated the process of healing match more plastics in the bone fracture. The PDGF can promote the OB differentiation, maturity, the formation of sclerotin and the expression of the OPG mRNAs, rising the coordination function to the OPG, RANKL in the whole process that bone fracture match more.