3-DIMENSIONAL SPATIAL RELATIONSHIP BETWEEN THE COLLAGEN FIBRILS AND THE INORGANIC CALCIUM-PHOSPHATE CRYSTALS OF PICKEREL (AMERICANUS-AMERICANUS) AND HERRING (CLUPEA-HARENGUS) BONE
3-DIMENSIONAL SPATIAL RELATIONSHIP BETWEEN THE COLLAGEN FIBRILS AND THE INORGANIC CALCIUM-PHOSPHATE CRYSTALS OF PICKEREL (AMERICANUS-AMERICANUS) AND HERRING (CLUPEA-HARENGUS) BONE
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DOI：
10.1016/0022-2836(91)90752-r
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发表时间：
1991-02-05
影响因子：
5.6
通讯作者：
GLIMCHER, MJ
中科院分区：
文献类型：
--
作者：
LEE, DD;GLIMCHER, MJ
高压（1.0 MV）电子显微镜和立体显微镜、电子探针微分析、电子衍射和三维计算机重建已被用来检查磷酸钙无机晶体与梭鱼和鲱鱼骨胶原纤维之间的空间关系。高压立体电子显微照片是在未钙化区域、在一些原纤维中仅沉积一种或仅几种晶体的区域以及在连续部分中包含逐渐更多的矿物晶体直到达到完全矿化阶段的圆柱形肌内骨的横截面获得的。高分辨率电子探针微量分析证实电子致密颗粒含有钙和磷。在矿化的最早阶段以及整个矿化过程中，晶体仅位于胶原纤维内；在胶原纤维之间的细胞外空间中未观察到游离的晶体。随着时间的推移，沉积在骨组织中的矿物质质量逐渐增加，基本上完全发生在胶原纤维内，包括完全矿化阶段。在此阶段，胶原原纤维的横截面轮廓被矿物质完全消除。位于原纤维表面上或靠近原纤维表面的少量晶体似乎延伸到原纤维之间的空间中非常短的距离。这些对钙化开始时的超微结构观察，清楚地显示磷酸钙晶体的成核开始于胶原原纤维的特定体积内，以及该现象随后的时间和空间序列，表明钙化完全在胶原原纤维内继续，直到实现最大钙化，增加了关于钙化的基本物理化学机制和所涉及的结构元素的重要信息。矿化起始位点的空间和时间独立性确定了这种超微结构位置单个胶原原纤维内代表独立的物理化学成核位点。这些发现与晶体必须首先沉积在基质囊泡或线粒体等其他成分中，然后在纤维间空间中释放和繁殖，直到它们最终到达并浸渍胶原纤维的孔区区域的提议完全不一致。连续横向和纵向切片的三维计算机重建显示沿着胶原纤维的周期性膨胀，对应于矿化过程中其轴向周期的孔区区域。仅在组织矿化程度较高的区域观察到原纤维的膨胀，这一结果表明，在原纤维内磷酸钙固相沉积逐渐增加的过程中，胶原原纤维可能会发生结构变化，以适应额外的矿物质质量。我们还使用中子衍射技术检查了用于高压电子光学研究的相同鱼骨，从中可以推定计算出胶原原纤维内可能可用于磷酸钙固体矿物相沉积的空间体积。与通过高压电子显微镜直接目视观察磷酸钙晶体的位置相反，根据中子衍射技术获得的数据进行的计算表明，鱼骨的胶原原纤维内没有足够的空间来容纳……中存在的所有矿物相。
High-voltage (1.0 MV) electron microscopy and stereomicroscopy, electron probe micro-analysis, electron diffraction and three-dimensional computer reconstruction, have been used to examine the spatial relationship between the inorganic crystals of calcium phosphate and the collagen fibrils of pickerel and herring bone. High-voltage stereo electron-micrographs were obtained of cross-sections of the cylinder-shaped intramuscular bones in uncalcified regions, in regions where only one or only several crystals had been deposited in some of the fibrils, and in successive sections containing progressively more mineral crystals until the stage of full mineralization was reached. High-resolution electron probe microanalysis confirmed that the electron-dense particles contained calcium and phosphorus. In the earliest stages of mineralization and progressing throughout the mineralization process, the crystals are located only within the collagen fibrils; crystals are not observed free in the extracellular spaces between collagen fibrils. The progressive increase in the mass of mineral deposited in the bone tissue with time occurs, essentially, completely within the collagen fibrils including the stage of full mineralization. At this stage, cross-sectional profiles of collagen fibrils are completely obliterated by mineral. A small number of crystals that are located on or close to the surface of the fibrils appear to extend a very short distance into the spaces between the fibrils. These ultrastructural observations of the very onset of calcification in which nucleation of the calcium phosphate crystals is clearly shown to begin within specific volumes of collagen fibrils, and of the subsequent temporal and spatial sequences of this phenomenon, which shows that calcification continues wholly within the collagen fibrils until maximum calcification is achieved, add important information on the basic physical chemical mechanism of the calcification and the structural elements that are involved.The spatial and temporal independence of the sites where mineralization is initiated establishes that such ultrastructural locations within individual collagen fibrils represent independent, physical chemical nucleationloci. The findings are totally inconsistent with the proposal that crystals must first be deposited in matrix vesicles, or other components such as mitochondria, and subsequently released and propagated in the interfibrillar space, until they eventually reach and impregnate the hole zone regions of the collagen fibrils.Three-dimensional computer reconstruction of serial transverse and longitudinal sections demonstrates periodic swellings along the collagen fibrils, corresponding to the hole zone region of their axial period as mineralization proceeds. Bulging of fibrils was observed only in the more heavily mineralized regions of the tissues, a result suggesting that structural changes of the collagen fibrils may occur to accommodate additional mineral mass during the progressive increase in the deposition of a solid phase of calcium phosphate within the fibrils.We have also examined the same fish bones used for high-voltage electron optical studies using neutron diffraction techniques, from which the volume of space within collagen fibrils potentially available for the deposition of a solid mineral phase of calcium phosphate can putatively be calculated. Contrary to the direct visual observations of the location of the calcium phosphate crystals by high-voltage electron microscopy, calculations based on the data obtained from neutron diffraction techniques reveal that there is not a sufficient volume of space within the collagen fibrils of fish bone to accommodate all of the mineral phase present in the …