Kang Y, Koepp H, Cole A A, Kuettner K E, Homandberg G A
Department of Biochemistry, Rush Medical College at Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois 60612-3864, USA.
J Orthop Res. 1998 Sep;16(5):551-6. doi: 10.1002/jor.1100160505.
According to numerous cadaveric, radiographic, and clinical studies, ankle and knee joints differ in susceptibility to osteoarthritis. To test for biochemical differences in susceptibility to damage, a chondrocytic chondrolysis system has been utilized. In this system, fibronectin fragments are added to cultured cartilage explants, resulting in enhanced release of catabolic cytokines, induction of matrix metalloproteinases, temporary suppression of proteoglycan synthesis, and consequently, severe loss of cartilage proteoglycan. We found that the addition of an amino-terminal thrombin-generated 29-kDa fibronectin fragment to cultured knee cartilage from 14 donors (average age: 53 years) usually caused a 30-50% decrease in proteoglycan content by day 7. However, of the ankle cartilage specimens examined from 21 donors (average age: 50 years), only three showed damage by day 7, one by day 14, and six by day 21, and 11 were not damaged until day 28. For eight of the donors (average age: 44 years), both knee and ankle cartilages were obtained: this allowed comparison between tissues from the same donor. The analysis showed that the ankle cartilage was much more refractory to damage than was the knee cartilage from the same donor. These data clearly show differences between ankle and knee cartilage in susceptibility to the fibronectin fragments and suggest the feasibility of use of these fragments for discerning differences in homeostasis of the ankle and knee cartilage.
根据大量尸体解剖、影像学和临床研究，踝关节和膝关节对骨关节炎的易感性存在差异。为了测试损伤易感性方面的生化差异，采用了一种软骨细胞溶解系统。在该系统中，将纤连蛋白片段添加到培养的软骨外植体中，导致分解代谢细胞因子释放增加、基质金属蛋白酶诱导、蛋白聚糖合成暂时抑制，进而导致软骨蛋白聚糖严重流失。我们发现，向来自14名供体（平均年龄：53岁）的培养膝关节软骨中添加氨基末端凝血酶生成的29 kDa纤连蛋白片段，到第7天时通常会导致蛋白聚糖含量下降30 - 50%。然而，在检查的来自21名供体（平均年龄：50岁）的踝关节软骨标本中，到第7天时只有3个出现损伤，到第14天时1个出现损伤，到第21天时6个出现损伤，11个直到第28天才出现损伤。对于8名供体（平均年龄：44岁），同时获取了膝关节和踝关节软骨：这使得能够比较来自同一供体的组织。分析表明，踝关节软骨比来自同一供体的膝关节软骨对损伤的耐受性要强得多。这些数据清楚地显示了踝关节和膝关节软骨在对纤连蛋白片段易感性方面的差异，并表明使用这些片段来区分踝关节和膝关节软骨稳态差异的可行性。
