Department of Oral Cell Biology and Functional Anatomy, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, the Netherlands; Biomechanics section, Department of Mechanical Engineering, KU Leuven, Leuven, Belgium.
Department of Oral Cell Biology and Functional Anatomy, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, the Netherlands.
J Mech Behav Biomed Mater. 2019 Feb;90:133-139. doi: 10.1016/j.jmbbm.2018.10.022. Epub 2018 Oct 14.
Nutrition of articular cartilage relies mainly on diffusion and convection of solutes through the interstitial fluid due to the lack of blood vessels. The diffusion is controlled by two factors: steric hindrance and electrostatic interactions between the solutes and the matrix components. Aging comes with changes in the cartilage structure and composition, which can influence the diffusion. In this study, we treated fibrocartilage of mandibular condyle with ribose to induce an aging-like effect by accumulating collagen crosslinks. The effect of steric hindrance or electrostatic forces on the diffusion was analyzed using either charged (Hexabrix) or uncharged (Visipaque) contrast agents. Osteochondral plugs from young equine mandibular condyles were treated with 500 mM ribose for 7 days. The effect of crosslinking on mechanical properties was then evaluated via dynamic indentation. Thereafter, the samples were exposed to contrast agents and imaged using contrast-enhanced computed tomography (CECT) at 18 different time points up to 48 h to measure their diffusion. Normalized concentration of contrast agents in the cartilage and contrast agent diffusion flux, as well as the content of crosslink level (pentosidine), water, collagen, and glycosaminoglycan (GAG) were determined. Ribose treatment significantly increased the pentosidine level (from 0.01 to 7.6 mmol/mol collagen), which resulted in an increase in tissue stiffness (~1.5 fold). Interestingly, the normalized concentration and diffusion flux did not change after the induction of an increased level of pentosidine either for Hexabrix or Visipaque. The results of this study strongly suggest that sugar-induced collagen crosslinking in TMJ condylar cartilage does not affect the diffusion properties.
关节软骨的营养主要依赖于溶质通过间质液的扩散和对流，这是由于缺乏血管所致。扩散受两个因素控制：溶质与基质成分之间的空间位阻和静电相互作用。随着年龄的增长，软骨结构和组成发生变化，这可能会影响扩散。在这项研究中，我们用核糖处理髁突纤维软骨，通过积累胶原交联来诱导类似老化的效应。使用带电荷的（Hexabrix）或不带电荷的（Visipaque）对比剂分析空间位阻或静电力对扩散的影响。用 500 mM 核糖处理来自年轻马下颌髁突的骨软骨塞 7 天。然后通过动态压痕评估交联对机械性能的影响。此后，将样品暴露于对比剂中，并在 48 小时内使用对比增强计算机断层扫描（CECT）进行 18 次不同时间点的成像，以测量它们的扩散。测量软骨中对比剂的归一化浓度和对比剂扩散通量，以及交联水平（戊糖）、水、胶原和糖胺聚糖（GAG）的含量。核糖处理显著增加了戊糖水平（从 0.01 增加到 7.6 mmol/mol 胶原），导致组织硬度增加（~1.5 倍）。有趣的是，无论是用 Hexabrix 还是 Visipaque，在诱导戊糖水平升高后，归一化浓度和扩散通量都没有变化。这项研究的结果强烈表明，TMJ 髁突软骨中糖诱导的胶原交联不会影响扩散特性。
