中文摘要：

目的探讨氟对体外培养成骨细胞中微小染色体维系蛋白3（minichromosome maintenance deficient3，MCM3）表达的影响。方法采用免疫组织化学技术、原位杂交技术以及SYBR GreenI嵌合荧光实时定量PCR（realtime RT-PCR）方法，检测不同剂量氟（0、5、10、20、40mg／L，处理10d）对体外培养成骨细胞中MCM3表达的影响。结果0、5、10、20、40mg／L各组细胞中均有MCM3蛋白及其mRNA表达，主要在细胞核中表达，与对照组比较，染氟实验组阳性表达强度高于对照组，阳性细胞数多于对照组，差异有统计学意义（P〈0．05），其中10mg／L组阳性表达高于其他实验组（P〈0．05），呈现双向作用。real time RT-PCR检测显示，各组均可检测到MCM3mRNA．相对定量比由对照组到高剂量组约为102：259：145：135：100：染氟实验组中5、10、20mg／L组表达量高于对照组和40mg／L组，以5mg／L组表达量最高，随着染氟剂量增加，基因表达量降低。结论不同剂量氟对成骨细胞中MCM3表达的影响不同，低剂量氟可以促进MCM3的表达，随剂量增加氟的促进作用减弱。

英文摘要：

Objective To detect the influence of fluoride on the gene expression of minichromosome maintenance deficient 3 （MCM3） in osteoblasts in vitro. Methods MCM3 gene expression was detected using immunohistochemical technique, in situ hybridization （ISH） and real-time fluorescence quantitative RT-PCR in vitro mouse osteoblasts exposed to fluoride of 0,5,10,20,40 mg/L for 10 days, respectively. Results We found that there were MCM3 proteins and mRNA expression in 0,5,10,20,40 mg/L groups, mainly in their nuceli. Compared to the control group, the positive intensity of groups exposed to fluoride was stronger, the positive numbers of osteoblasts were also higher, with a statistical significance （P 〈 0.05）, especially in 10 mg/L group （P 〈 0.05） a double-effect was observed. Real time RT-PCR detected MCM3 mRNA in all groups, the ratio of MCM3 mRNA quantity of control group to each experiment group 0,5,10,20,40 mg/L was 102 ： 259 ： 145 ： 135 ： 100, respectively, among which the value in 5 mg/L group is the highest. The higher the dose of fluoride, the less quantity of MCM3 mRNA. Conclusions Different doses of fluoride impose different effect on MCM3 gene expression of osteoblasts, the promoting effect attenuates along with the increase of the dose.