Höhling H J, Steffens H, Stamm G
Cell Tissue Res. 1976 Mar 16;167(2):243-63. doi: 10.1007/BF00224331.
The question of the initial mineralization in the epiphyseal plate has been investigated to date in specimens prepared by conventional electron microscopical techniques. As conventional techniques can produce artifacts, either a loss of mineral substance or a secondary nucleation, the mineralization process was investigated using freeze dried, vacuum embedded growth cartilage which was neither contrasted not stained and which had a very short contact with water. The prevailing theory that the first mineralization begins within extracellular matrix vesicles and that the mineralization outside these vesicles is a secondary process was confirmed. Mineralized matrix vesicles were found in the fully mineralized long septa down to the opening zone. In several cases a mineralization could be observed in those transverse septa in which organic substance was present between the cells. The typical radial arrangement of the apatitic needles and platelets in the matrix vesicles could be explained by the formation of a mineralization in an ionotropic gel, the orientation of the matrix macromolecules to be produced by a vectorial influx of calcium ions and phosphate groups coming from different directions. Thin strands of mineral substance with low contrast, which follow the direction of the longitudinal septum, were assumed to be the mineralized collagen fibrils. In several needles dot-like formations were seen and the distance between the middle of neighbouring dots was found to lie mainly in the range 30-56 A, while the lateral separation distance between the middle of closely packed parallel chains and needles was found to lie mainly in the range 30-42 A. Parallel periodic structures which could be visualized in apatitic chains and needles 20-40 A in diameter were assumed to be the 8.2 A-(100)-lattice planes of apatite, being an indication that these formations already possess criteria of the apatite lattice.
迄今为止，已采用传统电子显微镜技术制备的标本对骨骺板中的初始矿化问题进行了研究。由于传统技术可能会产生假象，即矿物质的损失或二次成核，因此使用冷冻干燥、真空包埋的生长软骨对矿化过程进行了研究，这种软骨既未进行对比也未染色，且与水的接触时间非常短。普遍的理论认为，首次矿化始于细胞外基质小泡内，而这些小泡外的矿化是一个二次过程，这一理论得到了证实。在直至开放区的完全矿化的长间隔中发现了矿化的基质小泡。在几个案例中，可以观察到那些细胞间存在有机物质的横向间隔中有矿化现象。基质小泡中磷灰石针状晶体和片状晶体的典型径向排列可以通过离子型凝胶中矿化的形成来解释，基质大分子的取向是由来自不同方向的钙离子和磷酸基团的矢量流入产生的。沿着纵向间隔方向的低对比度矿物质细链被认为是矿化的胶原纤维。在几根针状晶体中可以看到点状结构，相邻点中心之间的距离主要在30 - 56埃范围内，而紧密排列的平行链和针状晶体中心之间的侧向间隔距离主要在30 - 42埃范围内。在直径为20 - 40埃的磷灰石链和针状晶体中可以看到的平行周期性结构被认为是磷灰石的8.2埃 - (100)晶格平面，这表明这些结构已经具备了磷灰石晶格的标准。
