Changes in expression of proteinases and tissue inhibitors of metalloproteinases in advance of osteoarthritis

软骨基质的逐渐丧失是骨关节炎（OA）病理的一个标志。先前的研究表明，几种蛋白酶的表达在软骨破裂中起关键作用。在本研究中，我们研究了正常、早期和晚期OA膝关节软骨内关键蛋白酶（MMP-13、ADAMTS-5）和金属蛋白酶组织抑制剂（TIMPs）的表达，并特别关注软骨组织内的区域差异。本研究结果表明，在早期骨性关节炎发生的软骨中，TIMP-2、3和4的表达降低，而MMP-13和ADAMTS-5的表达升高。这项研究的结果可能会揭示OA病理的一个新的方面。

Gradual loss of cartilage matrix is a hallmark of pathology of osteoarthritis (OA). Previous studies have shown that the expression of several proteinases play a pivotal role in cartilage breakdown. In this study, we investigated the expression of key proteinases (MMP-13, ADAMTS-5) together with that of tissue inhibitors of metalloproteinases (TIMPs) within cartilage from normal, early, or advanced OA knee joints, paying special attention to the regional difference within cartilage tissue.The result of this study has shown that the expression of TIMP-2, 3 and 4 reduced in cartilage where early OA changes occur, before the elevation of MMP-13 and ADAMTS-5 expression. The result of this study might shed light on a novel aspect of OA pathology.