Coupling Effect of Water and Proteoglycans on the In Situ Toughness of Bone.
Coupling Effect of Water and Proteoglycans on the In Situ Toughness of Bone.
复制标题
DOI：
10.1002/jbmr.2774
复制
发表时间：
2016-05
期刊：
影响因子：
--
通讯作者：
Jiang JX
中科院分区：
文献类型：
--
作者：
Wang X;Xu H;Huang Y;Gu S;Jiang JX
蛋白聚糖（Proteoglycans，PGs）是骨细胞外基质中的一类非胶原蛋白，主要由核心蛋白和糖胺聚糖（Glycosaminoglycans，GAGs）组成。GAG是高极性的并且带负电荷，因此具有将水分子吸引到基质中的强烈趋势。我们在这项研究中假设，只有当水存在时，骨骼中的PG才在维持组织韧性方面发挥关键作用。为了验证这一假设，我们使用了一种新的纳米划痕试验来测量用和不用PNGase F处理的人尸体骨的原位韧性，PNGase F是一种特异性地从核心蛋白中去除GAG的N-连接寡糖的酶。从6名（N=6）年龄在51.5±5.17岁之间的男性供体的中段骨干股骨后侧制备皮质骨样本。使用生化和组织化学测定来验证N-连接寡糖是否被PNGase F从骨基质中去除。通过对湿骨和脱水骨的测试，研究了水和PGs之间的耦合作用对骨的原位韧性的影响。双因素方差分析表明，去除GAG对湿骨样品的原位韧性有显着影响。相反，去除GAG对干骨的韧性没有显着影响。这项研究的结果首次表明，只有当存在水时，糖胺聚糖才在骨骼的原位韧性中发挥关键作用，反之亦然，只有当存在糖胺聚糖时，水才在骨骼中发挥增塑剂的作用。
Proteoglycans (PGs) are one type of non-collagenous proteins in the extracellular matrix of bone, which primarily contain a core protein and glycosaminoglycans (GAGs). GAGs are highly polar and negatively charged, thus having a strong tendency in attracting water molecules into the matrix. We hypothesized in this study that PGs in bone play a pivotal role in sustaining the toughness of the tissue only when water is present. To test the hypothesis, we used a novel nanoscratch test to measure the in situ toughness of human cadaveric bone treated with and without PNGase F, an enzyme that specifically removes the N-linked oligosaccharides of GAGs from core proteins. Cortical bone specimens were prepared from the posterior aspect of mid-diaphyseal femurs of six (N=6) male human donors between 51.5±5.17 years old. Biochemical and histochemical assays were used to verify whether N-linked oligosaccharides were removed from bone matrix by PNGase F. By testing wet and dehydrated bone specimens, the coupling effect between water and PGs on the in situ toughness of bone was investigated. The two-way ANOVA analyses showed that removal of GAGs had significant effects on the in situ toughness of wet bone samples. In contrast, the removal of GAGs did not show significant effects on the toughness of dry bone. The results of this study, for the first time, suggest that GAGs play a pivotal role in the in situ toughness of bone only when water is present, and vice versa water functions as a plasticizer in bone only when GAGs are present.