氟对小鼠釉鞘蛋白基因表达的影响

Ameloblastin gene expression in fluoride-induced mus musculus incisors in mice

目的探讨氟对小鼠釉鞘蛋白基因表达的影响。方法在建立小鼠中度及重度氟斑牙模型的基础上,应用原位杂交技术观察对照组(饮用去离子水)、低氟组(饮水F-为50 mg/L)、高氟组(饮水F-为150 mg/L)小鼠下切牙发育过程中,釉鞘蛋白mRNA在成釉细胞增殖分化期、分泌期及成熟期的表达情况。结果对照组小鼠下切牙形态正常,牙齿表面呈半透明、乳白色,光滑而有光泽。镜下釉鞘蛋白mRNA在成釉细胞增殖分化期表达为阴性;分泌初期细胞内及新生釉基质中开始出现弱阳性表达;至分泌期,细胞内及新生釉基质中均呈强阳性表达;成熟釉质中无釉鞘蛋白mRNA的阳性表达。低氟组小鼠下切牙表面有或宽或窄的白垩色釉质矿化不良区与矿化较好的釉质条带相交替,镜下釉鞘蛋白mRNA在釉牙本质界附近的釉基质中有弱阳性表达。高氟组小鼠的下切牙表面大面积白垩色区域伴局灶性釉质缺损,镜下成釉细胞排列紊乱;在成釉细胞分泌期,釉基质分泌几乎中断;釉鞘蛋白mRNA在新生釉基质表面及釉牙本质界处阳性表达,在成釉细胞分泌期,其表达多次中断,并且在深层釉基质中也可见到釉鞘蛋白mRNA的较强阳性表达。结论氟影响釉鞘蛋白mRNA在成釉细胞、釉基质中的表达,过高浓度的氟周期性抑制成釉细胞分泌釉基质的功能,从而导致釉质的矿化不全、矿化不均及局灶性缺损。

Objective To study the effect of fluorine on the ameloblastin gene expression of mouse mus musculus.Methods On the basis of setting up a model for medium-and high-level dental fluorosis of mus musculus,this research analyzed the space-time expression of ameloblastin in inferior incisor growth period of mus musculus by using in situ hybridization.Results The results indicated that in control group（drank deionized water）,the formation of mus musculus＇ inferior incisor was natural,and the tooth surface was semitransparent,ivory white,smooth and glossy.Ameloblastin mRNA was negative under microscope in the ameloblast proliferation differentiation period;it showed weakly positive expression in intra-cellular and new-birth enamel matrix in secretion initial stage.It showed strongly positive expression in intra-cellular and new-birth enamel matrix when it came to secretion phase.There was no positive expression of ameloblastin mRNA in the mature stage.In low-fluorine group（the concentration of F in drinking water was 50mg/L）,there were broad or narrow chalkiness,ill enamel-mineral stripes and comparatively good emanel-mineral stripes alternately on the inferior incisor of mus musculus.Ameloblastin mRNA showed weakly positive expression when it developed from dentoenamel junction to new-birth enamel matrix.In high-fluorine group（the concentration of F in drinking water was 150mg/L）,there were wide areas of chalkiness and focal enamel damnification on the inferior incisor of mus musculus.Ameloblasts were disorganized under microscope.The exudation of enamel matrix almost stopped in ameloblast secretion phase.Ameloblastin mRNA showed positive expression on the surface of dentoenamel junction of new-birth enamel matrix and dentoenamel junction while the expression discontinued for several times during the exudation of enamel matrix and it showed comparatively strong positive expression in mineralized enamel matrix.Conclusion Overdosed fluorine can affect the expression of ameloblastin mRNA in ameloblast and enamel matrix,and it can intermittently influence the exudation of enamel matrix at the same time.Then,it will induce ill mineralization of enamel,unsymmetrical mineralization and focal damnification.