A Study On Tumor Necrosis Factor Receptor-associated Factor6 Experss In Physiological Root Resorption Of Human Primary Teeth

Objective:The replacement of primary and permanent teeth is the strict regulation of physiological processes in vivo. Odontoclast is the main functional cell involved the physiological root resorption of human primary teeth. TRAF6 is the key molecule in the signals regulating during the procedur of differentiation and maturity of osteolasts/odontoclast. This experiment is to study expression of TRAF6 in physiological root resorption of human primary teeth, and variation of TRAF6 during different stages of physiological root resorption of human primary teeth. Try to investigate the function of TRAF6 in the physiological root resorption of human primary teeth.Methods:1. Permanent tooth and primary tooth resorpted were decalcified,embedded,sliced,TRAF6 was observed by the immunohistoche-mical technique and in situ hybridization method. Im-pro-plas 6.0 analysis system measured the optical density of the two groups in odontoclast, odontoblast and pulp fibroblast. SPSS13.0 statistical analysised software to analyze the different expression of TRAF6;2. The physiological root resorption of primary tooth were classified into early, middle and late three groups by the length of root, to observe TRAP, TRAF6 protein and TRAF6mRNA expression in odontoclast by the immunohistochemical technique and in situ hybridization method. Im-pro-plas 6.0 analysis system measured the optical density of three various stages, SPSS 13.0 statistical analysis software analysised changes in their expression patterns of three stages. Results:1. In the immunohistochemical experiment and the in situ hybridization experiment,TRAF6 positive signals were seen in odontoclast, odontoblast and pulp fibroblast of the physiological root resorption of primary tooth. But in permanent tooth, odontoclast can't be observed, and TRAF6 negative signals in odontoblast and pulp fibroblast. Compared between the same cells of two groups, using t-test, P＜0.01; and in physiological root resorption of primary teeth, the optical density of the odontoclast were significantly different from that of the odontoblast and pulp fibroblast, P＜0.01; the odontoblast and pulp fibroblast showed no difference.2. In the odontoclast of the physiological root resorption of primary tooth, TRAP positive signals in early, middle and late groups, and compared by single factor analysis of variance, P＜0.05, the highest optical density was in middle groups. The optical density of the positive signals of TRAF6 were higher in early and middle groups,—there was no significantly different between this two groups,—but significantly different compared with late group, P＜0.05. That the optical density of three staining change had a positive correlation with odontoclast activity, and in the basic consistent with the value curve.Conclusion:1.In the odontoclast of the physiological root resorption of primary tooth, TRAF6 positive signals showed brown staining by the immunohistochemical technique and in situ hybridization method. Suggesting that TRAF6 may be involved in odontoclast differentiation and activity, causing physiological root resorption of human primary teeth.2. In the immunohistochemical experiment, the highest optical density of TRAP in odontoclast was in middle group of the physiological root resorption of primary tooth. Suggesting that the function of TRAP was strongest in middle group.3. In the immunohistochemical experiment and the in situ hybridization experiment, the optical density of TRAF6 positive signals in odontoclast were higher in early and middle groups,—there was no significantly different between the two groups,—but significantly different compared with late group. Suggesting that the function of TRAF6 was strongest in early, middle group, as well as odontoclast. 4. The changes of the optical density of three staining—TRAP, TRAF6 in the immunohistochemical experiment and TRAF6 in the in situ hybridization experiment—had a positive correlation with odontoclast activity, and in the basic consistent with the value curve.