Lee D A, Bentley G, Archer C W
IRC in Biomedical Materials, Institute of Orthopaedics, University College and Middlesex School of Medicine, Brockley Hill, Stanmore, UK.
Osteoarthritis Cartilage. 1994 Sep;2(3):175-85. doi: 10.1016/s1063-4584(05)80067-6.
Articular cartilage comprises a small number of cells embedded within a matrix primarily composed of collagen and proteoglycan (PG). The functional integrity of the tissue is highly dependent on the maintenance of matrix structure, which, in turn, is controlled by the chondrocytes. In normal tissue there is a slow but steady turnover of matrix components such that their levels remain constant. In certain diseased states the equilibrium is upset, resulting in a net loss of matrix components. The object of the present study was to artificially upset the synthetic/loss equilibrium by enzymic depletion and assess the ability of chondrocytes to respond by increasing PG synthesis. Cultured bovine articular cartilage explants were depleted using enzymes as follows; 10 U/ml Streptomyces hyaluronidase (induced a 30% loss of PG), 2000 U/ml testicular hyaluronidase (70% loss of PG) and 100 U/ml collagenase (35% loss of PG) and control (6% loss of PG). Collagenase also induced a 50% loss of collagen. Collagenase treatment induced a 50% stimulation of PG synthesis above control levels. Elevated synthesis levels were maintained for 9 days. Testicular hyaluronidase induced a brief elevation in PG synthesis on day 3 of culture. Streptomyces hyaluronidase treatment did not cause an alteration in the rate of PG synthesis above control levels. Histological examination indicated that collagenase-treated explants formed outgrowths consisting of rounded chondrocytes within a fine fibrous matrix which stained intensely with safranin-O, indicating a high concentration of PG. The production of repair-like outgrowths may explain the elevated PG synthesis rates measured. It appears, therefore, that collagen and matrix organization is more important than PG levels in the control of PG synthesis in articular cartilage explant cultures.
关节软骨由少量嵌入主要由胶原蛋白和蛋白聚糖（PG）组成的基质中的细胞构成。组织的功能完整性高度依赖于基质结构的维持，而基质结构又由软骨细胞控制。在正常组织中，基质成分有缓慢但稳定的更新，使得它们的水平保持恒定。在某些疾病状态下，这种平衡被打破，导致基质成分净损失。本研究的目的是通过酶促消耗人为打破合成/损失平衡，并评估软骨细胞通过增加PG合成来做出反应的能力。使用以下酶对培养的牛关节软骨外植体进行消耗处理：10 U/ml 透明质酸酶链霉菌（导致PG损失30%）、2000 U/ml 睾丸透明质酸酶（PG损失70%）和100 U/ml 胶原酶（PG损失35%）以及对照组（PG损失6%）。胶原酶还导致胶原蛋白损失50%。胶原酶处理使PG合成比对照水平提高了50%。合成水平升高持续了9天。睾丸透明质酸酶在培养第3天引起PG合成短暂升高。透明质酸酶链霉菌处理未导致PG合成速率高于对照水平的改变。组织学检查表明，经胶原酶处理的外植体形成了由圆形软骨细胞组成的突起，位于精细的纤维基质中，该基质用番红O染色强烈，表明PG浓度高。修复样突起的产生可能解释了所测得的PG合成速率升高。因此，在关节软骨外植体培养中，胶原蛋白和基质组织在控制PG合成方面似乎比PG水平更重要。
