Lees S
Bioengineering Department Forsyth Dental Center, Boston, MA.
Connect Tissue Res. 1987;16(4):281-303. doi: 10.3109/03008208709005616.
The relative magnitudes of mineral, organic and water contents of dense mammalian bone are calculated by a new theory based on recent findings: (1) The neutron diffraction studies of mineralized tissues with different densities demonstrated an inverse relationship between wet density and the equatorial diffraction spacing of the collagen. (2) The neutron studies showed there was very little mineral within the collagen fibrils. (3) A generalized packing model for collagen has been advanced to show how the equatorial spacing can be varied depending on tissue type, water content, and mineral content. (4) The water content of collagen fibrils when calculated from the generalized packing model matches the experimentally determined values for rat tail tendon fibers, bone matrix, and fully mineralized bone. A computational model was developed based on the generalized packing model. It provides a unifying approach to explain many features of mineralized fibrous collagenous tissues. The results are presented as estimates of the mineralized collagen fibril density, the volume fraction of collagen in bone, the density of the extrafibrillar space, the fraction of the e.f. space occupied by mineral and the ratio of mineral within collagen to total mineral content, each expressed as a function of wet bone density. A useful data base, available from previous studies, related mineral, organic and water weight fractions to wet bone density, for a density range from 1.7 g/cc for deer antler to 2.7 g/cc for porpoise petrosal. A second order polynomial was found for each weight fraction component, with bone density as the input variable, with a standard deviation less than 2% of total bone weight. This permits the bone properties to be related to a single variable, the wet bone density. It is seen that compacting the collagen fibrils as well as reducing the organic component weight fraction are two important factors determining the structure of the mineralized osteoid. It was concluded that voids and pore spaces may occupy at least 5% of the bone volume.
致密哺乳动物骨骼中矿物质、有机物和水含量的相对大小是根据一项基于近期研究结果的新理论计算得出的：（1）对不同密度矿化组织的中子衍射研究表明，湿密度与胶原蛋白的赤道衍射间距呈反比关系。（2）中子研究表明，胶原纤维内的矿物质很少。（3）已经提出了一种通用的胶原蛋白堆积模型，以展示赤道间距如何根据组织类型、含水量和矿物质含量而变化。（4）根据通用堆积模型计算出的胶原纤维含水量与大鼠尾腱纤维、骨基质和完全矿化骨的实验测定值相符。基于通用堆积模型开发了一个计算模型。它为解释矿化纤维状胶原组织的许多特征提供了一种统一的方法。结果以矿化胶原纤维密度、骨中胶原蛋白的体积分数、纤维外空间的密度、纤维外空间中被矿物质占据的比例以及胶原蛋白内矿物质与总矿物质含量的比值的估计值呈现，每个值都表示为湿骨密度的函数。一个有用的数据库可从先前的研究中获得，该数据库将矿物质、有机物和水重量分数与湿骨密度相关联，密度范围从鹿鹿角的1.7 g/cc到鼠海豚岩部的2.7 g/cc。发现每个重量分数成分都有一个二阶多项式，以骨密度作为输入变量，标准偏差小于总骨重量的2%。这使得骨特性能够与单个变量——湿骨密度相关联。可以看出，压实胶原纤维以及降低有机成分重量分数是决定矿化类骨质结构的两个重要因素。得出的结论是，空隙和孔隙空间可能至少占据骨体积的5%。
