CIMPARATIVE STUDY OF DENTAL BASEMENT MEMBRANE

1.在猴和大鼠牙齿发育过程中，发现与内釉上皮基底膜相关的特征性纤维层是基底膜的高度特化的纤维网状层，其异常富含基底小管，10nm宽的微纤维样结构。牙乳头细胞突起插入纤维网状层，其表面与许多平行的基管紧密相连。通过高分辨率的观察，相邻的基管之间的空间由1.5 - 3 nm宽的细丝连接，这些细丝垂直于基管的轴。这些结果表明，牙乳头细胞的突起通过1.5 - 3nm宽的细丝与基管相连。免疫过氧化物酶染色显示纤维连接蛋白沿着基底小管以及在突起和基底小管之间的空间内的存在。这一结果表明，这些1.5 - 3nm宽的细丝是由纤连蛋白组成的。巴索 关于我们 在本研究中，纤维网状层中的被认为是基底膜结合的微纤维的小微束可能作为锚定装置沿着基底膜沿着锚定牙乳头细胞。间充质细胞的这种排列方式对于牙齿发育过程中成牙本质细胞的成功分化至关重要。与成熟期成釉细胞相关的基膜样结构由透明层和致密层组成。后者是由一个很好的“索”网络，基底膜的主要成分。它与第三层200 nm宽的松散索网络密切相关。在没有脱矿的标本中，第三层和部分致密层钙化，形成釉质的边缘。这个特定区域的电子密度更高，矿物晶体的大小、形状和排列与釉质的其他部分不同。此外，矿化似乎是沿着索进行。这些观察结果表明，该致密层是高度特化的基底膜，其通过该基底膜本身的一部分的矿化来介导成熟阶段成釉细胞与釉质的牢固结合，该基底膜本身的一部分成为釉质的一部分。少

1. In the developing tooth of monkey and rat a characteristic fibrillar layer associated with the basement membrane of inner enamel epithelium was found to be a highly specialized lamina fibroreticularis of the basement membrane which is unusually rich in basotubules, 10nm wide microfibril-like structures. Dental papilla cell processes were inserted into the lamina fibroreticularis and their surface was closely associated with numerous parallel basotubles. With high-resolution observations the space between neighbouring basotubules were bridged by 1.5-3 nm wide filaments running perpendicular to the axis of basotubules. These results indicate that the processes of dental papilla cells are linked to groups of basotubules by mean of 1.5-3nm wide filaments. Immunoperoxidase staining showed the presence of fibronectin along baseotubules as well as within the space between the process and basotubules. This result indicates that these 1.5-3nm wide filaments are composed of fibronectin. Basot … More ubules, thought to be basement membrane-incorporated microfibrils, in the lamina fibroreticularis in this study are likely to function as an anchoring device to immobilize dental papilla cells along the basement membrane. Such an arrangement of mesenchymal cells is known to be crucial for the successful differentiation of odontoblasts in the developing tooth.2. A basement membrane-like structure associated with the maturation stage ameloblasts of the monkey was composed of a lamina lucida and lamina densa. The latter was made up of a fine "cords" network, the major constituent of the basement membrane. It was closely associated with the third layer of a 200nm wide looser cord network. In specimens without demineralization the third layer and a part of the lamina densa were calcified, and it formed the edge of the enamel. The particular area had a higher electron density, and the size, shape, and arrangement of mineral crystals were different from those of the rest of the enamel. Also, mineralization appeared to be proceeding along the cords. These observations indicate that this dense layer is a highly specialized basement membrane which mediates the firm association of maturation stage ameloblasts with the enamel by means of the mineralization of a part of this basement membrane itself which becomes integrated as a part of the enamel. Less