EFFECTS OF CHRONIC FLUORIDE EXPOSURE ON MORPHOMETRIC PARAMETERS DEFINING THE STAGES OF AMELOGENESIS AND AMELOBLAST MODULATION IN RAT INCISORS
EFFECTS OF CHRONIC FLUORIDE EXPOSURE ON MORPHOMETRIC PARAMETERS DEFINING THE STAGES OF AMELOGENESIS AND AMELOBLAST MODULATION IN RAT INCISORS
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DOI：
10.1002/ar.1092370212
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发表时间：
1993-10-01
影响因子：
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通讯作者：
DENBESTEN, PK
中科院分区：
文献类型：
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作者：
SMITH, CE;NANCI, A;DENBESTEN, PK
在雌性Sprague-Dawley大鼠连续爆发的下颌门牙中，研究了成釉细胞对长期（6周）暴露于100ppm氟化物的反应，并与对照组大鼠进行了比较，对照组大鼠接受了类似的饮食（Teklad L-356），但饮用水中没有氟化钠。治疗后，两组动物血管内灌注戊二醛，取切牙直接取1 mm厚Epon切片进行光镜形态学分析。其他动物静脉注射钙黄蛋白（绿色荧光），4小时后注射二甲酚橙（红色荧光），以显示末端光滑的成釉细胞调制带，从而可以量化这些牙齿成熟区内调制波的产生和运动的相关参数。结果表明，大鼠门牙在正常淀粉发生过程中表现出四种主要变化，这些变化可能与慢性氟化物处理有关。首先，成釉细胞在完成分泌阶段进入成釉发育成熟阶段时产生比正常釉质层更薄的釉质层。成熟区内的牙釉质器官细胞，尤其是乳突层的牙釉质器官细胞高度明显低于正常水平。第三，与成熟珐琅质相关的成釉细胞，部分溶解或完全溶解在EDTA中，其调节速度比正常情况慢得多。在一些地方，成釉细胞在每个周期中保持褶皱的时间比正常长30%。这打乱了通常的模式，使得这些成釉细胞在单位时间内完成的总调制周期减少。第四，牙釉质蛋白从成熟的牙釉质层中流失的速度比正常情况慢40%左右。数据表明，成釉细胞检测到细胞外分解和/或珐琅质蛋白损失的延迟，并且它们的反应是保持褶边的间隔比平时更长（正反馈）。(C) 1993 Wiley-Liss, Inc。
The response of ameloblasts to long-term (6 weeks) exposure to 100 ppm fluoride was examined in continuously erupting mandibular incisors of female Sprague-Dawley rats as compared to control rats receiving a similar diet (Teklad L-356) but no sodium fluoride in their drinking water. After treatment, animals from both groups were perfused intravascularly with glutaraldehyde, and the incisors were removed and processed for light microscope morphometric analyses directly from 1 mum thick Epon sections. Other animals were injected intravenously with calcein (green fluorescence) followed 4 hours later by xylenol orange (red fluorescence) in order to reveal smooth-ended ameloblast modulation bands and thereby allow quantification of parameters related to the creation and movement of modulation waves within the maturation zone of these teeth. The results indicated that rat incisors expressed four major changes in normal amelogenesis which could be attributed to the chronic fluoride treatment. First, ameloblasts produced a thinner than normal enamel layer by the time they completed the secretory stage and entered the maturation stage of amelogenesis. Second, enamel organ cells within the maturation zone, especially those from the papillary layer, were shorter in height than normal. Third, ameloblasts related to maturing enamel in areas where it,was partially soluble and/or fully soluble in EDTA modulated at a rate that was much slower than normal. In some locations ameloblasts remained ruffle-ended for as much as 30% longer than normal per cycle. This upset the usual pattern such that fewer total modulation cycles were completed per unit time by these ameloblasts. Fourth, enamel proteins were lost from the maturing enamel layer at a rate that was about 40% slower than normal. The data suggested that ameloblasts detected the delay in the extracellular breakdown and/or loss of enamel proteins and they responded by remaining ruffle-ended for longer intervals than usual (positive feedback). (C) 1993 Wiley-Liss, Inc.