Laboratory for Soft Tissue Research, Tissue Engineering, Regeneration and Repair Program, The Hospital for Special Surgery, New York, NY 10021, United States.
Laboratory for Soft Tissue Research, Tissue Engineering, Regeneration and Repair Program, The Hospital for Special Surgery, New York, NY 10021, United States.
J Biomech. 2014 Feb 7;47(3):645-52. doi: 10.1016/j.jbiomech.2013.11.050. Epub 2013 Dec 10.
The objective of this study was to develop an in vitro cartilage degradation model that emulates the damage seen in early-stage osteoarthritis. To this end, cartilage explants were collagenase-treated to induce enzymatic degradation of collagen fibers and proteoglycans at the articular surface. To assess changes in mechanical properties, intact and degraded cartilage explants were subjected to a series of confined compression creep tests. Changes in extracellular matrix structure and composition were determined using biochemical and histological approaches. Our results show that collagenase-induced degradation increased the amount of deformation experienced by the cartilage explants under compression. An increase in apparent permeability as well as a decrease in instantaneous and aggregate moduli was measured following collagenase treatment. Histological analysis of degraded explants revealed the presence of surface fibrillation, proteoglycan depletion in the superficial and intermediate zones and loss of the lamina splendens. Collagen cleavage was confirmed by the Col II-3/4Cshort antibody. Degraded specimens experienced a significant decrease in proteoglycan content but maintained total collagen content. Repetitive testing of degraded samples resulted in the gradual collapse of the articular surface and the compaction of the superficial zone. Taken together, our data demonstrates that enzymatic degradation with collagenase can be used to emulate changes seen in early-stage osteoarthritis. Further, our in vitro model provides information on cartilage mechanics and insights on how matrix changes can affect cartilage's functional properties. More importantly, our model can be applied to develop and test treatment options for tissue repair.
本研究的目的是开发一种体外软骨降解模型，以模拟早期骨关节炎中观察到的损伤。为此，对软骨标本进行胶原酶处理，以诱导关节表面胶原纤维和蛋白聚糖的酶解降解。为了评估力学性能的变化，对完整和降解的软骨标本进行了一系列的受限压缩蠕变试验。采用生化和组织学方法确定细胞外基质结构和组成的变化。我们的结果表明，胶原酶诱导的降解增加了软骨标本在压缩下经历的变形量。胶原酶处理后，表观渗透率增加，瞬时和聚集模量降低。降解标本的组织学分析显示表面出现了纤维状皱纹，浅层和中层的蛋白聚糖耗竭以及板层明亮带的丧失。通过 Col II-3/4Cshort 抗体证实了胶原的断裂。降解标本的蛋白聚糖含量显著下降，但仍保持总胶原含量。对降解样本的重复测试导致关节表面逐渐塌陷和浅层的压实。总之，我们的数据表明，胶原酶的酶解降解可用于模拟早期骨关节炎中观察到的变化。此外，我们的体外模型提供了有关软骨力学的信息，并深入了解基质变化如何影响软骨的功能特性。更重要的是，我们的模型可用于开发和测试组织修复的治疗方案。
