| Objective: To study the antagonism of vitamin E (VE) and calcium on rat dental fluorosis occurring relationship with expression of Notch-1 and fibroblast growth factor 8(FGF8) as signals in rat tooth development ,we explored pathogenesis of dental fluorosis and the antagonism of VE and calcium on the molecular level to offer evidence for treatment and prevention research of dental fluorosis in the clinical.Methods: 80 SD rats were randomly divided into 8 groups: control group(distilled water) , sodium fluoride group, sodium fluoride + low-dose VE group, sodium fluoride + standard-dose VE group, sodium fluoride + high-dose VE group, sodium fluoride + low-dose calcium group, sodium fluoride + standard-dose calcium group, sodium fluoride + high-dose calcium group. During the experiment, we observed daily activities, eating, excretion, response and dental situation about the rats. Weekly we took photographs on the surface of rat incisor lip using a digital camera and recorded changes of the tooth surface color and weight. After 11 weeks the rats was treatmented, HE staining was used to observe the morphology of the ameloblasts, immunohisto-chemistry assay was used to determine the expression of Notch-1 and enzyme-linked assay was used to determine the expression of the FGF8. All data were statistically analyzed using SPSS17.0 system.Results: During the amelogenesis the ameloblasts are undergoing a serial of changes,which are closely relevant to their functions. At different stages the morphological characteristic of the ameloblasts and their functions are quite different. The expression of Notch 1 was initiated in early bell stage in inner-enamal epithelium pre-odontoblasts and dental papilla mesenchymal cells. Et was repeatedly expressed in ameloblasts after dental tissue was formed. In the control group ameloblasts had normal morphology and arranged orderly, But in the sodium fluoride groups the ameloblasts arranged multilayerly, the enamel matrix was confused and the expression of Notch 1 was significantly lower than that of the control group. In different concentrations of VE, calcium group, with the VE, calcium concentration increased, the expression of Notch 1 gradually increased in the rat tooth germ epithelium, but still lower than the control group.Statistical analysis of the expression of Notch-1 showed: (1) control group, NaF group, NaF + low-dose VE group, NaF + standard-dose VE group, NaF + high-dose VE group, statistical analysis showed significantly difference (P <0.05); (2) control group, NaF group, NaF + low-dose Ca group, NaF + standard-dose Ca group, NaF + high-dose Ca group , statistical analysis showed significantly difference (P <0.05).Statistical analysis of the expression of FGF8 showed: (1) control group, NaF group, NaF + low-dose VE group, NaF + standard-dose VE group, NaF + high-dose VE group, statistical analysis showed no difference (P> 0.05); (2) control group, NaF group, NaF + low-dose Ca group, NaF + standard-dose Ca group, NaF + high-dose Ca group ,statistical analysis showed significantly difference (P <0.05).Conclusion: the antagonism of calcium toward dental fluorosis may be in relation to enhance the expression of the Notch-1 and of FGF8, VE antagonism may be associated with increasing the expression of the Notch-1 . |
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