Huang Jian, Wang Xi, Zhang Tian-Lan, Wang Kui
Department of Chemical Biology, Peking University School of Pharmaceutical Sciences, 38 Xueyuan Road, Beijing 100191, PR China.
Joint Bone Spine. 2009 Mar;76(2):176-83. doi: 10.1016/j.jbspin.2008.04.017. Epub 2008 Dec 6.
Noncollagenous proteins (NCPs) play distinct and overlap roles in controlling the mineralization of bone, while the relationship between the NCPs and the mineral phase in osteoporotic bone is nebulous. Ovariectomized (OVX) rats, as an animal model for osteopenia, were used in this study to evaluate the impact of NCPs on mineral metabolism in osteopenia development.
Bone mineral was characterized with small-angle X-ray scattering study, extended X-ray absorption fine structure analysis, inductively coupled plasma mass spectroscopy, thermogravimetric and chemical analyses. NCPs were extracted from bone matrix, and analyzed with sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). A constant composition titration system was used in the kinetic study of re-mineralization of bone residues after various extractions.
Bone density was reduced, whereas no significant changes were observed in the composition, crystal thickness and crystal structural parameters of minerals from OVX rat bone. The total content of NCPs in each extract decreased in the OVX group, but no selective loss of particular proteins was observed. The difference in mineralization kinetics between the OVX rat bone and the sham rat bone was resulted mainly from the mineral-bound NCPs.
The reduced quantity and unchanged quality of bone mineral seem to be positively associated with the total amount of NCPs and the proportions between some major NCPs in OVX rats, respectively.
非胶原蛋白（NCPs）在控制骨矿化过程中发挥着独特且相互重叠的作用，然而骨质疏松性骨中NCPs与矿化相之间的关系尚不明确。本研究采用去卵巢（OVX）大鼠作为骨质减少的动物模型，以评估NCPs对骨质减少发展过程中矿物质代谢的影响。
通过小角X射线散射研究、扩展X射线吸收精细结构分析、电感耦合等离子体质谱、热重分析和化学分析对骨矿物质进行表征。从骨基质中提取NCPs，并采用十二烷基硫酸钠聚丙烯酰胺凝胶电泳（SDS-PAGE）进行分析。在各种提取后骨残渣再矿化的动力学研究中使用恒定组成滴定系统。
OVX大鼠骨密度降低，但其骨矿物质的组成、晶体厚度和晶体结构参数未观察到显著变化。OVX组各提取物中NCPs的总含量降低，但未观察到特定蛋白质的选择性丢失。OVX大鼠骨与假手术大鼠骨矿化动力学的差异主要源于与矿物质结合的NCPs。
骨矿物质数量减少但质量不变似乎分别与OVX大鼠中NCPs的总量以及一些主要NCPs之间的比例呈正相关。
