The Expression And Significance Of Osterix Protein In Human Tooth Development

To understanding the regulation mechanism in toothdevelopment is the hot spot and difficult problems in dental pulpbiology , there are extraordinary theory and clinic significance notonly in damage repair of dental tissue , dental pulp and toothregeneration, but also in good model of multi-germinal layerorgan development.More recently, osterix (Osx), a zinc finger-transcriptionfactor related with bone differentiation and morphogenesis wasfound by Nakashimi in 2002. Osterix (Osx) is osteoblast-specifictranscription factors and essential for the development of a matureosteoblast phenotype and bone forming. Osx functions geneticallydownstream of Runx2, which controls both growth anddifferentiation in osteoblast. Gene expression Osx-deficient micelack osteoblasts and do not form endochondralorintramembranous bones. It is likely that Osx control differentstages of osteoblast differentiation. Osx protein only appeardin development bone. Nakashima found that in mice embryo andnew bone tissue Osx gene was detected early in differentialcartilage cell of 13.5d embryo, and then widely in cell with bonedevelopment. The mesenchymal of dental embryo was alsopositive expression. The objective of this research is to observethe expression site of Osx during tooth development by theimmunohistochemistry method in order to explore the functionand significiance of Osx. And reveal the signal network in toothdevelopment. Nevertheless,there are not reports on the functionalexpresstion of Osx and tooth germ development.The specimens of human tooth germ in different stages wereobtained from aborted embryos in second hospital of Jilinuniversity and HongQi community clinic . the stage of mandibleand maxillary speciments from aborted embryo range 7 weeks-28weeks. The speciments were paraffined. Immunohistochemistrystaining technique was used to test the expression of Osx duringhuman tooth germ development ..The results suggest that Osx gene expresses in the cytoplasm.There are different distribution in different stage of toothdevelopment .In the bud stage, the epithelial express Osx protein,the dental lamina epithelial was less expression .In the cap stage,the expression of Osx in the enamel organ contained the outerenamel epithelium, inner enamal epithelium and stellate reticulumwere strongly positive expressions, and the expression of Osxin the inner enamal epithelium and enamel knot obviouslyconcentrated. The expression dental papilla was observed inweakly.In the bell stage, odontoblast, ameloblast and the adjacentdental papilla highly express the Osx, enamel-dentinal junction,the new formative enamel and dentinal tubule also express theOsx protein.Conclusion: The expression of Osx has its own specificityin different stage of human dental germ development.Osxparticipates in the differentiation and mature of odontoblast,ameloblast, the signal transmission between cells, it regulating thesecreting of enamel ,dentin and the process of biologicalmineralizing. Osx may plays an important roly in human toothdevelopment.