短期高浓度氟对小鼠磨牙成釉细胞形态及骨形成蛋白-4表达的影响

Effect of short exposure to high levels of fluoride on cellular structural and the expression of BMP-4 in ameloblasts of mouse molar

目的:通过研究短期高浓度氟对小鼠磨牙成釉细胞形态及骨形成蛋白-4(bone morphogenetic protein-4,BMP-4)表达的影响,探讨氟牙症形成的可能机制。方法:选择4d龄的ICR小鼠共32只,随机分为2组,每组16只,再分实验动物和对照动物各半。实验动物单次腹腔注射剂量分别为10mg/kg和20mg/kg的NaF,对照动物单次腹腔注射等剂量的NaCl,注射量均为10μl/g。24h后处死动物。采用HE染色、免疫组化染色观察高浓度氟对小鼠磨牙不同分化阶段成釉细胞形态及BMP-4的表达,采用SPSS13.0软件对数据进行分析。结果:分泌早、晚期和过渡期的成釉细胞对短期暴露高浓度F-敏感,实验动物分泌晚期和过渡期的成釉细胞中BMP-4的表达明显弱于对照动物,差异有统计学意义(P<0.01),而成熟期成釉细胞未见明显变化。结论:短期高浓度氟可抑制BMP-4在分泌晚期和过渡期成釉细胞中的表达,影响釉质发育。

Objective ：To study the effect of short exposure to high levels of fluoride on structure and the BMP-4 expression of ameloblasts of mouse molar and explore the possible formation mechanisms of dental fluorosis. Methods： 32 4-day-old ICR mice were randomly divided into two groups. The experimental animals and the control animals were shared equal numbers in each group. The experimental animals were received a single intraperitoneal dose of 20 （n =8） and 10 （n =8） mg NaF/kg（body weight） respectively, equal doses of NaC1 were given to the controls （n = 8 for each group）. The injected volume was kept constant （10μl/g）. After 24 h all mice were sacrificed. HE and immunohistochemical stainings were used to observe the structural changes and the expression of BMP-4 in ameloblasts of mouse molar at different stages. SPSS 13.0 software package was used to analyze the data. Results：The early and late secretory/transitional ameloblasts were sensitive to a short-lasting but high dose of F^-. The immunohistochemistry results demonstrated that in experimental animals, the expression of BMP-4 was weaker than that in control animals with the significant differences （ P 〈 0.01 ）. No remarkable differences were found in maturation ameloblasts. Conclusion： Short exposure to high levels of fluoride can inhibit the expression of BMP-4 in the late secretory and transitional ameloblasts and lead to the abnormal development of enamel matrix.