title: Type X collagen, a natural component of mouse articular cartilage: association with growth, aging, and osteoarthritis.
abstract: 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.
authors.affiliation: University of Turku, Finland.
authors.forename: I
authors.initials: I
authors.lastname: Eerola
authors.forename: H
authors.initials: H
authors.lastname: Salminen
authors.forename: P
authors.initials: P
authors.lastname: Lammi
authors.forename: M
authors.initials: M
authors.lastname: Lammi
authors.forename: K
authors.initials: K
authors.lastname: von der Mark
authors.forename: E
authors.initials: E
authors.lastname: Vuorio
authors.forename: A M
authors.initials: AM
authors.lastname: Säämänen
mesh_terms: 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
chemical_list: D012333:RNA, Messenger; D003094:Collagen