Résumé
Objective To study the induction of amelogenin in formation of hard tissues in the pulp tissues,to provide experimental foundation for research in formation of hard tissues induced with amelogenin.Methods Sixteen male Wistar rats were divided into control group and experimental group.Cells and matrix structures and amelogenin expression in the growing ends of cyclophosphamide(CP)-affected incisors were examined by histological and immunohistochemical methods.Results Experiment group:extensive edematous changes were noted in the apical pulp tissue of the incisor associated with disappearance of odontoblasts facing to presecretory and secretory ameloblasts. The cell layer of young ameloblasts was therefore lined directly with pulp tissue in which some osteodentin-like tissue was present near the ameloblasts. Immunoreactions for amelogenins were observed in the labial side of the pulp,particularly around the newly induced hard tissues in the affected region. Conclusion Amelogenins has induction in formation of hard tissues in dental pulp following the inhibition of formation of odontoblasts by CP.
Résumé
Objective :The study discussed the relationship between the cell differentiation and its func-tion differentiation of enamel organ durrng the development of enamel ,explained the meaning of shape andfunction of SA and RA in the mature enameloblasts. Methods:The rats were fixed with pouring hearts ,em-bed with Epon and GMA resin,made semi-thin slice ,stained with toluidine blue and histochemistry, thenwe observed the changes of histomorphology and the law of distribution of enamel. Results:The develop-memt of tooth germ of rat incisor could be divided into proliferation stage, difference stage and maturestage. Enameloblasts expressed special periodic changes in mature stage :SA legion and RA legion present-ed altermately. Histochemical study indicated that most of amelogenin stayed in enamel matrix and othersdiffused to dentin, dental tube and odontoblast layer. Conclusion: (1) The proliferation stage, differencestage and mature stage of tooth of development of enamel organ in rat were similar to the bud stage ,capstage and bell stage of human being. There was a relationship between the RA legion in mature enam-eloblast and mineral substance pouring into them. RA legion was presented because water and protein lost.)That amelogenin spread into dentin could promote the odontoblast differentiation and induce dentin calci-fication.