Structure-function relationships in enzymatically modified articular cartilage
Structure-function relationships in enzymatically modified articular cartilage
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DOI：
10.1159/000074628
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发表时间：
2003-01-01
影响因子：
2.7
通讯作者：
Helminen, HJ
中科院分区：
文献类型：
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作者：
Rieppo, J;Töyräs, J;Helminen, HJ
本研究旨在揭示牛髌骨关节软骨的结构与功能关系。胶原酶、软骨素酶ABC和弹性酶用于软骨结构、组成和功能特性的控制和选择性酶修饰。利用定量偏振光显微镜、红花素o染色切片的数字密度测定以及生化和生物力学技术，定量评估酶解的效果。组织组成和结构相关参数与软骨压痕刚度相关。一般来说，酶消化后的组织改变仅限于表面软骨。所有的酶降解都引起了表面蛋白聚糖（PG）的消耗。胶原酶也能引起可检测到的表面胶原损伤，但不会引起软骨纤维性颤动或组织肿胀。定量显微技术在检测这些变化方面比生化方法更敏感。软骨的杨氏模量在酶处理后下降，表明组织明显软化。表面区PG浓度是杨氏模量的主要决定因素（r(2) = 0.767, n = 72, p < 0.001）。本研究结果表明，组织pg和胶原蛋白的特异性酶解可以为阐明软骨的结构-功能关系提供可重复的实验模型。这些模型的效果模拟了早期骨关节病中观察到的变化。生物力学测试和定量显微技术被证明是检测表面结构和成分变化的有力工具，而对整个未钙化软骨的生化测量则不太敏感。
The present study is aimed at revealing structure-function relationships of bovine patellar articular cartilage. Collagenase, chondroitinase ABC and elastase were used for controlled and selective enzymatic modifications of cartilage structure, composition and functional properties. The effects of the enzymatic degradations were quantitatively evaluated using quantitative polarized light microscopy, digital densitometry of safranin O-stained sections as well as with biochemical and biomechanical techniques. The parameters related to tissue composition and structure were correlated with the indentation stiffness of cartilage. In general, tissue alterations after enzymatic digestions were restricted to the superficial cartilage. All enzymatic degradations induced superficial proteoglycan ( PG) depletion. Collagenase also induced detectable superficial collagen damage, though without causing cartilage fibrillation or tissue swelling. Quantitative microscopic techniques were more sensitive than biochemical methods in detecting these changes. The Young's modulus of cartilage decreased after enzymatic treatments indicating significant softening of the tissue. The PG concentration of the superficial zone proved to be the major determinant of the Young's modulus (r(2) = 0.767, n = 72, p < 0.001). Results of the present study indicate that specific enzymatic degradations of the tissue PGs and collagen can provide reproducible experimental models to clarify the structure-function relationships of cartilage. Effects of these models mimic the changes observed in early osteoarthrosis. Biomechanical testing and quantitative microscopic techniques proved to be powerful tools for detecting the superficial structural and compositional changes while the biochemical measurements on the whole uncalcified cartilage were less sensitive.