Ultrastructural observations of dental epithelial cells and enameloid during enameloid mineralization and maturation stages in stingrays, Urolophus aurantiacus, an elasmobranch
Ultrastructural observations of dental epithelial cells and enameloid during enameloid mineralization and maturation stages in stingrays, Urolophus aurantiacus, an elasmobranch
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黄貂鱼、Urolophus aurantiacus（软骨鱼）牙釉质矿化和成熟阶段牙上皮细胞和釉质的超微结构观察
DOI：
10.1093/oxfordjournals.jmicro.a023702
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
J. Akai
中科院分区：
文献类型：
--
作者：
I. Sasagawa;J. Akai
利用光镜和透射电镜研究了黄貂鱼（Urolophus aurantiacus）牙胚中类釉质矿化和成熟过程中类釉质细胞和牙上皮细胞的精细结构。结果表明，牙上皮细胞在类牙釉质形成的后期参与了类牙釉质基质的变性和移除，其高峰出现在矿化阶段。在矿化阶段，在釉质层中观察到大量的致密晶体。在脱矿切片中，保留了细胞膜的小碎片和电子致密的原纤维。内牙上皮细胞具有发育良好的光滑内质网和许多含有电子致密物质的囊泡、液泡和颗粒。IDE细胞远端下可见较厚的层状致密。牙外上皮细胞具有许多线粒体、小的电子致密体、囊泡和中间丝，毛细血管常靠近牙外上皮细胞。在成熟阶段，IDE细胞高度降低，在远端细胞质中有许多溶酶体、囊泡和线粒体。ODE细胞变小了。膜层致密几乎不存在，IDE细胞的远端似乎经常与类瓷质表面直接接触。
The fine structure of enameloid and dental epithelial cells in tooth germs of sepia stingrays,Urolophus aurantiacus, an elasmobranch, during enameloid mineralization and enameloid maturation was investigated using light and transmission electron microscopy. The findings suggest that dental epithelial cells are involved in the degeneration and removal of the enameloid matrix during later stages of enameloid formation, and its peak is during the mineralization stage. During the mineralization stage, a large number of denned crystals were observed in the enameloid layer. In demineralized sections, small fragments of cell membrane and electron-dense fibrils remained. The inner dental epithelial (IDE) cells contained well-developed smooth endoplasmic reticulum, and many vesicles, vacuoles and granules containing electron-dense substance. Thick lamina densa was found beneath the distal end of the IDE cells. The outer dental epithelial (ODE) cells possessed many mitochondria, small electron-dense bodies, vesicles and intermediate filaments, and the capillaries usually approached the ODE cells. During the maturation stage, the IDE cells were reduced in height, and had many lysosomal bodies, vesicles, and mitochondria in the distal cytoplasm. The ODE cells became smaller. The lamina densa was almost absent and the distal end of the IDE cells often seemed to be in direct contact with the enameloid surface.