Effects of fluoride on rat dental enamel matrix proteinases
Effects of fluoride on rat dental enamel matrix proteinases
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DOI：
10.1016/s0003-9969(02)00117-6
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发表时间：
2002-11-01
影响因子：
3
通讯作者：
Li, W
中科院分区：
文献类型：
--
作者：
DenBesten, PK;Yan, Y;Li, W
釉质氟中毒的特征是随着釉质的成熟，孔隙率增加，釉质基质蛋白的去除延迟。釉原蛋白是分泌期牙釉质中的主要基质蛋白。随着釉质成熟，釉原蛋白被许多釉质蛋白酶水解，包括基质金属蛋白酶-20（MMP-20或釉质溶解素）和丝氨酸蛋白酶。在这里，摄入的氟化物对釉质基质中蛋白酶的相对活性的影响和氟化物对MMP-20活性的具体影响进行了检查。蛋白酶活性相对于总釉质基质蛋白测定釉质基质解剖大鼠给予0，50，或100份每106氟化物在他们的饮用水的荧光分析。为了确定氟化物对MMP-20活性的特异性影响，通过十二烷基硫酸钠（SDS）-聚丙烯酰胺凝胶电泳（PAGE）比较在0、2、5、10或100 μ M氟化物存在下重组MMP-20（rMMP-20）对全长重组人釉原蛋白的水解。此外，开发了荧光肽测定来量化针对富含酪氨酸的釉原蛋白肽切割位点的酶活性。在成熟后期，氟暴露大鼠单位蛋白的总蛋白酶活性低于对照组大鼠。这一体内研究结果表明，氟化物摄入可以改变成熟釉质中活性蛋白酶的相对量。在100 μ M F存在下，rMMP-20在中性pH下对釉原蛋白的水解减少。在肽测定中，rMMP-20的活性显着降低浓度低至2 μ M的氟化物在pH 6，在pH 7.2没有显着的效果。这些体外试验表明，微摩尔浓度的氟化物可以改变金属蛋白酶的活性，特别是当pH值降低到6.0时。这些研究表明，氟对釉质基质蛋白酶分泌或活性的影响可能与釉质和其他矿化组织中氟中毒的病因有关。(C)2002爱思唯尔科技有限公司版权所有。
Enamel fluorosis is characterised by increased porosity and a delay in the removal of enamel matrix proteins as the enamel matures. Amelogenin is the primary matrix protein in secretory-stage dental enamel. As enamel matures, amelogenins are hydrolysed by a number of enamel proteinases, including matrix metalloprotemase-20 (MMP-20 or enamelysin) and serine proteinase. Here, the effect of ingested fluoride on the relative activity of proteinases in the enamel matrix and the specific effect of fluoride on MMP-20 activity were examined. Proteinase activity relative to total enamel matrix protein was measured by fluorescence assay of enamel matrix dissected from rats given 0, 50, or 100 parts per 106 fluoride in their drinking water. To determine the specific effect of fluoride on the activity of MMP-20, the hydrolysis of a full-length recombinant human amelogenin by recombinant MMP-20 (rMMP-20) in the presence of 0, 2,5, 10 or 100 muM fluoride was compared by sodium dodecyl sulphate (SDS)-polyacrylamide gel electrophoresis (PAGE). In addition, a fluorescent peptide assay was developed to quantify enzyme activity against the tyrosine-rich amelogenin peptide cleavage site. In the late maturation stage, total proteinase activity per unit protein was lower in the fluoride-exposed rats than in the control rats. This in vivo finding indicates that fluoride ingestion can alter the relative amount of active proteinase in mature enamel. Hydrolysis of amelogenin at neutral pH by rMMP-20 was reduced in the presence of 100 muM F. In the peptide assay, rMMP-20 activity was significantly reduced by concentrations of fluoride as low as 2 muM at pH 6, with no significant effect at pH 7.2. These in vitro assays show that micromolar concentrations of fluoride can alter metalloproteinase activity, particularly when the pH is reduced to 6.0. These studies suggest that the effects of fluoride on enamel matrix proteinase secretion or activity could be involved in the aetiology of fluorosis in enamel and other mineralising tissues. (C) 2002 Elsevier Science Ltd. All rights reserved.