Chevalier X, Groult N, Emod I, Planchenault T
Department of Rheumatology, Hôpital Henri-Mondor, Creteil, France.
Br J Rheumatol. 1996 Jun;35(6):506-14. doi: 10.1093/rheumatology/35.6.506.
The osteoarthritis (OA) process is characterized by the progressive destruction of articular cartilage. There is a loss of cartilage proteoglycan content and disorganization of the collagen network, as well as an increase in other non-collagenous protein such as fibronectin (Fn). Increased proteolytic activity may lead to the degradation of native Fn and generation of Fn proteolytic fragments. Among them, the 45 kDa collagen-binding Fn fragment can be autoactivated in vitro into a 40 kDa fragment. This 40 kDa fragment induces an average of 30% of proteoglycan release per day from human OA cartilage explants and can degrade proteoglycan using dead cartilage sections. Proteoglycan-degrading activity related to the 40 kDa Fn fragment was decreased up to 66% by fetal calf serum (10%), but was not prevented by protein synthesis inhibitors (cycloheximide or actinomycin D). The action of this 40 kDa Fn fragment was greater on OA than on normal cartilage. This study suggests that enzymatic activity induced by the 40 kDa collagen-binding fragment of Fn might be involved in cartilage matrix turnover.
骨关节炎（OA）的病程以关节软骨的进行性破坏为特征。存在软骨蛋白聚糖含量的丧失和胶原网络的紊乱，以及其他非胶原蛋白如纤连蛋白（Fn）的增加。蛋白水解活性增加可能导致天然Fn的降解和Fn蛋白水解片段的产生。其中，45 kDa的胶原结合Fn片段在体外可自动激活为40 kDa的片段。这个40 kDa的片段每天可诱导人OA软骨外植体平均释放30%的蛋白聚糖，并且可以使用死软骨切片降解蛋白聚糖。与40 kDa Fn片段相关的蛋白聚糖降解活性被胎牛血清（10%）降低了66%，但未被蛋白质合成抑制剂（环己酰亚胺或放线菌素D）阻止。这个40 kDa Fn片段对OA软骨的作用比对正常软骨的作用更大。本研究表明，Fn的40 kDa胶原结合片段诱导的酶活性可能参与软骨基质的周转。
