Increased collagen and aggrecan degradation with age in the joints of Timp3−/− mice
Article first published online: 27 FEB 2007
Copyright © 2007 by the American College of Rheumatology
Arthritis & Rheumatism
Volume 56, Issue 3, pages 905–909, March 2007
How to Cite
Sahebjam, S., Khokha, R. and Mort, J. S. (2007), Increased collagen and aggrecan degradation with age in the joints of Timp3−/− mice. Arthritis & Rheumatism, 56: 905–909. doi: 10.1002/art.22427
- Issue published online: 27 FEB 2007
- Article first published online: 27 FEB 2007
- Manuscript Accepted: 28 NOV 2006
- Manuscript Received: 15 AUG 2006
- Canadian Arthritis Network of Centers of Excellence
- Canadian Institutes of Health Research
- Shriners of North America
To investigate the in vivo effect of an imbalance between metalloproteinases and their inhibitors, tissue inhibitors of metalloproteinases (TIMPs), in mouse articular cartilage.
Hind joints of Timp3−/− and wild-type mice were examined by routine staining and by immunohistochemical analysis using antibodies specific for type X collagen and for the neoepitopes produced on proteolytic cleavage of aggrecan (… VDIPEN and … NVTEGE) and type II collagen. The neoepitope generated on cleavage of type II collagen by collagenases was quantitated in sera by enzyme-linked immunosorbent assay.
Articular cartilage from Timp3-knockout animals (ages ≥6 months) showed reduced Safranin O staining and an increase in …VDIPEN content compared with cartilage from heterozygous and wild-type animals. There was also a slight increase in … NVTEGE content in articular cartilage and menisci of Timp3−/− animals. Chondrocytes showed strong pericellular staining for type II collagen cleavage neoepitopes, particularly in the superficial layer, in knockout mice. Also, there was more type X collagen expression in the superficial zone of articular cartilage, especially around clusters of proliferating chondrocytes, in the knockout mice. More type II collagen cleavage product was found in the serum of Timp3−/− mice compared with wild-type animals. This increase was significant in 15-month-old animals.
These results indicate that TIMP-3 deficiency results in mild cartilage degradation similar to changes seen in patients with osteoarthritis, suggesting that an imbalance between metalloproteinases and TIMP-3 may play a pathophysiologic role in the development of this disease.