过量氟对大鼠切牙基质金属蛋白酶-20及其组织抑制剂表达的影响

Effects of Overdosed Fluoride on Rat's Incisor Expression of Matrixmetalloproteinase-20 and Tissue Inhibitors of Metalloproteinase-2

目的研究过量氟对大鼠切牙生长过程中基质金属蛋白酶-20(MMP-20)和基质金属蛋白酶组织抑制剂-2(TIMP-2)表达的影响,探讨氟斑牙的发病机制。方法选择20只Wistar大鼠,随机分为对照组和给氟组。8周后处死动物,获取切牙标本,免疫组化染色观察MMP-20和TIMP-2在大鼠切牙中的表达定位和氟对二者表达的影响。结果MMP-20和TIMP-2在分泌期成釉细胞、成牙本质细胞以及成釉器均有阳性表达,给氟组MMP-20的表达明显弱于对照组,差异有统计学意义(P<0.01);TIMP-2在两组的表达无显著性差异(P>0.05)。结论过量氟可抑制MMP-20的表达,MMP-20和TIMP-2表达失衡,TIMP-2的抑制作用加强,致使釉基质蛋白清除延迟,导致矿化不全和釉质缺损。

[Abstract] Objective To investigate the effects of overdosed fluoride on the expression of MMP-20 and TIMP-2 in rat incisor. Methods 20 Wistar rats were randomly divided into experiment group and control group. The distilled water was given in control group. 100 mg/L fluoride- was given in experiment group. After 8 weeks treatment, the rats were killed. Immunohistochemical staining was used to observe the expression of MMP-20 and TIMP-2 in rat incisors. Results Immunohistoehemieal results demonstrated the presence of MMP-20 and TIMP-2 protein in ameloblasts, odontoblasts, stratum intermedium and the stellate retieulum of rat incisor. The imagination analysis results showed that the expression of MMP-20 was reduesed in experiment group （P〈0.01）, and the expression of TIMP-2 had no significant difference （P〉0.05）. Conclusion The overdosed fluoride inhibits the secretion of MMP-20 and leads to the disturbed balance between MMP-20, TIMP-2 in rat incisor, which leads to the delay of the amelogenin removal and the enamel demineralization.