Krane S M, Goldring M B
Department of Medicine, Harvard Medical School, Massachusetts General Hospital, Boston 02114.
Eur J Rheumatol Inflamm. 1990;10(1):4-9.
The ability of articular cartilage to withstand repeated mechanical loading with relatively little wear over a lifetime results from the properties of the extracellular matrix (ECM) and the optimal function of the chondrocytes which are responsible for the synthesis and presumably maintenance of this ECM. The properties of the ECM are accounted for by the relationship of the major aggregating, polyanionic, negatively charged proteoglycans with their potent viscoelastic properties to the network of collagens and several noncollagenous proteins. The major collagen (type II) interacts with type IX collagen in a highly specific manner. Type IX collagen has a chondroitin sulfate side chain and can also bind to the aggregating proteoglycans through a basic amino terminal domain. In inflammation, injury and probably repeated wear, function of the chondrocytes is disturbed, mediated by the action of potent cytokines, which results in release of degradative enzymes and alterations in the pattern of synthesis of the ECM. Identification of the critical cytokines and the sequence of events that result from their action should provide the basis for rational prophylaxis and therapy of disorders such as osteoarthritis and rheumatoid arthritis. Articular cartilage has unique mechanical properties which permit repeated mechanical loading with relatively little wear over a lifetime. These properties result from the special character of the extracellular matrix (ECM) and optimal functioning of the component cells (chondrocytes) which are responsible for the synthesis and presumably, maintenance of this matrix. Articular chondrocytes survive and perform these critical functions in an anaerobic environment remote from the vasculature and must derive their nutrition from the synovial fluid.(ABSTRACT TRUNCATED AT 250 WORDS)
关节软骨在一生中能够承受反复的机械负荷且磨损相对较小，这源于细胞外基质（ECM）的特性以及软骨细胞的最佳功能，软骨细胞负责合成并可能维持这种ECM。ECM的特性取决于主要的聚集性、多阴离子、带负电荷的蛋白聚糖与其强大的粘弹性之间的关系，以及胶原蛋白和几种非胶原蛋白的网络。主要的胶原蛋白（II型）以高度特异性的方式与IX型胶原蛋白相互作用。IX型胶原蛋白具有硫酸软骨素侧链，还可通过碱性氨基末端结构域与聚集性蛋白聚糖结合。在炎症、损伤以及可能的反复磨损中，软骨细胞的功能会受到强大细胞因子作用的干扰，这会导致降解酶的释放以及ECM合成模式的改变。识别关键细胞因子及其作用导致的一系列事件，应为骨关节炎和类风湿关节炎等疾病的合理预防和治疗提供依据。关节软骨具有独特的机械性能，使其在一生中能够承受反复的机械负荷且磨损相对较小。这些性能源于细胞外基质（ECM）的特殊性质以及负责合成并可能维持这种基质的组成细胞（软骨细胞）的最佳功能。关节软骨细胞在远离脉管系统的无氧环境中存活并执行这些关键功能，且必须从滑液中获取营养。（摘要截选至250词）
