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Objective: To to using fluorine Ward coal baked corn establish coal dental fluorosis rat model to observe the changes in SD rats teeth after food the fluorinated coal bake corn ameloblasts morphogenesis and fluorine withered rat tooth development process death inhibit gene expression of Bcl-2, Bax ameloblasts expression, and to explore the molecular mechanisms and prevention and control measures of coal dental fluorosis. Methods: The experiment consists of two parts: 1, animal selection, grouping and feeding experimental coal fluorine the dental animal model: 50-week-old SD rats, male and female, were randomly divided into five groups, (n = 10), male and female each 5 min cage feeding, every 12 hours, alternating light and dark, free diet, were: ① high fluoride group: feeding the fluoride content of 88mg/kg corn, together with the flour, soy flour, fish meal, bone meal, wheat bran and salt; the ② fluoride group: fed with fluoride content of 56mg/kg corn, together with the flour, soybean meal, fish meal, bone meal, wheat bran and salt; (3) low fluoride group: feed containing fluorine content of 30mg/kg of corn, with wheat flour, soybean meal, fish meal, bone meal, wheat bran and salt; ④ positive control group: give drink 100mg / L aqueous solution of sodium fluoride, food ingredients corn as non-fluoride corn, with wheat flour, soybean meal, fish meal, bone meal, wheat bran and salt; ⑤ negative control group: the amount of fluoride in drinking water is 0.08ppm, non-fluoride formula feed. Observe indicators and methods (1) the beginning of the experiment and after a week respectively weighed rats Generally, records the changes in body weight. ② conducted urine and blood samples collected in the end of the end of January and March, respectively, with a fluoride ion selective electrode method for the determination of fluoride ion content in the urine and serum. ③ check the occurrence of dental fluorosis in late January and late March, according to the grading standards of dental fluorosis of rats in each group dental fluorosis score, before and after the experiment with a vernier caliper measurement of tooth length. (4) when significant dental fluorosis was observed in rats teeth that were sacrificed to remove the teeth and mandible. Conventional paraffin sections, HE staining of rat ameloblasts and odontoblasts morphological changes. Using immunohistochemical methods ameloblasts related apoptosis gene Bcl-2 and Bax expression was observed. Under an optical microscope, the slice digitized image input multimedia analysis system, the strength of the positive expression of conversion to digital signals, a semi-quantitative analysis of the immunohistochemistry positive area of ??staining intensity, each patient randomly selected 6 Perspective, Determination of Bcl 2 and Bax immunohistochemistry optical density values ??averaged as a measured value. Results: 1, general conditions and changes in body weight of rats: negative control group of rats hair smooth, shiny and responsive, the experimental group of rats coat lose their luster, unresponsive, negative control group rats weight gain than The obvious experimental group, the difference was significant (P <0.05). Fluorine groups in experimental rats blood fluorine, urine fluoride level in late March were higher than the end of January, the difference was statistically significant (P <0.01); experimental rats blood fluoride, urine fluoride levels over the same period for the high fluoride group> > low fluoride group, negative control group, pairwise comparison, the difference was statistically significant (P <0.01). 3, the model replication 3 months after the naked eye observation to the negative control group rats teeth translucent brownish yellow, smooth gloss, experimental rats teeth into a yellowish brown yellow, some areas opaque chalky change, or even white stripes or spots, followed by the formation of white patches. Severe enamel defects, tooth wear shortened length. Desert rat dental fluorosis scoring: With the dyeing the fluorine time the extended and exposed to fluoride dose increase, the experimental group rat teeth most of the brown stripes disappear, the teeth appear white chalk-like, most of them associated with dental defects; largest number of high fluoride group were scored 3, reaching 8 cases in fluoride group, the low fluoride group, positive control group in turn reduced, only three cases of the positive control group, negative control group Points are 0; high fluoride group of fluorine group with low fluoride group and the control group, the difference was statistically significant (P <0.01). Tooth length measurement: experimental group rat tooth length was significantly shorter in the end of March in the end, the more significant difference (P <0.01), the shortest length of the teeth of high fluoride group exposed to fluoride group and negative control group, with group There was a significant difference (P <0.05). HE staining results: negative control group rat incisor from the root end to the cut end into ameloblasts oval gradually mature into high columnar ameloblasts high columnar differentiation, arranged in a uniform, enamel maturity into ameloblasts gradually transformed by the tall columnar dwarf cuboidal the odontoblast neatly was palisade dentin uniform during visible dentinal tubules, uniform distribution of dental pulp cells; the low fluoride ameloblasts irregular arrangement, the original tall columnar structure grow shorter, a small number of cells distorted, disordered arrangement of odontoblasts; the high fluoride composed very irregular arrangement of ameloblasts, a large number of cells distorted enamel thinning. 7, the expression of Bcl-2 and Bax's: the experimental group, Bcl-2 and Bax in ameloblasts, odontoblasts and dental pulp cells were expressed, located in the nuclear membrane of the cell cytoplasm and nucleus of brownish yellow particles, basically the same part of the expression of each experimental group, the high fluoride the group expression weakest, negative control group, the highest expression. Semi-quantitative analysis comparing exposed to fluoride group and negative control group, the difference was significant (P <0.01). Only high fluoride group and the fluoride group differences between exposed to fluoride between the groups was significant (P <0.05). Conclusion: 1, successfully established a rat model of coal dental fluorosis. With the extension of the time exposed to fluoride and exposed to fluoride dose increase, the severity of dental fluorosis in rats also increased. 3, excessive fluoride can lead to rat ameloblasts original and some high columnar dwarf cubic transformation occurred disorganized, distorted morphological changes. Excessive fluoride on the expression of Bcl-2 and Bax protein expression in rat You inhibition speculated that it may induce ameloblast apoptosis, thereby affecting enamel development, and ultimately lead to abnormalities of the teeth. 5
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