Type X collagen, a natural component of mouse articular cartilage: association with growth, aging, and osteoarthritis.
OBJECTIVE
To perform a systematic study on the production and deposition of type X collagen in developing, aging, and osteoarthritic (OA) mouse articular cartilage.


METHODS
Immunohistochemistry was employed to define the distribution of type X collagen and Northern analyses to determine the messenger RNA levels as an indicator of the synthetic activity of the protein.


RESULTS
Type X collagen was observed in the epiphyseal and articular cartilage of mouse knee joints throughout development and growth. Type X collagen deposition in the transitional zone of articular cartilage became evident toward cessation of growth, at the age of 2-3 months. The most intense staining for type X collagen was limited to the tidemark, the border between uncalcified and calcified cartilage. Northern analysis confirmed that the type X collagen gene is also transcribed by articular cartilage chondrocytes. Intense immunostaining was observed in the areas of OA lesions, specifically, at sites of osteophyte formation and surface fibrillation. Type X collagen deposition was also seen in degenerating menisci.


CONCLUSIONS
This study demonstrates that type X collagen is a natural component of mouse articular cartilage throughout development, growth, and aging. This finding and the deposition of type X collagen at sites of OA lesions suggest that type X collagen may have a role in providing structural support for articular cartilage.
Eerola
I
I
University of Turku, Finland.
Salminen
H
H
Lammi
P
P
Lammi
M
M
von der Mark
K
K
Vuorio
E
E
Säämänen
A M
AM
D000375:Aging / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D015152:Blotting, Northern; D015153:Blotting, Western; D002358:Cartilage, Articular / Q000378:metabolism*; D003094:Collagen / Q000378:metabolism*; D007124:Immunoenzyme Techniques; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010003:Osteoarthritis / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis
D012333:RNA, Messenger; D003094:Collagen