Ultrastructural immunolocalisation of bone sialoprotein in the osteocartilagenous interface of the equine third carpal bone.
BACKGROUND
One of the most common causes of lameness in racehorses is osteoarthritis (OA). Pathogenesis is not clear and pathological processes of the different joint tissues interact in often progressive events. The interface between cartilage and newly synthesised bone has been shown to be particularly enriched in bone sialoprotein (BSP), a cell-binding matrix protein.


OBJECTIVE
To establish whether changes in the concentration of BSP may serve as a marker for early biochemical changes of the subchondral bone.


METHODS
Articular cartilage, cartilage/bone interface and subchondral bone of the proximal third carpal bone from 3 Standardbred trotters were analysed ultrastructurally for the presence of BSP in normal and degenerative areas.


RESULTS
A marked increase of BSP in the cartilage/bone interface with degenerative changes of the bone and cartilage compared to the morphologically intact cartilage/bone interface was noted, but levels of the protein were distinctly lower in the distal bone.


CONCLUSIONS
The results indicate that BSP has the potential to be used as a marker for changes in bone metabolism in the subchondral bone.


CONCLUSIONS
Tools to monitor early biochemical changes within the connective tissues of the joint in vivo are essential in studies of the pathogenesis of OA. These could be used to monitor and understand such changes in relation to load, exercise, training programmes, inflammation and the development of OA.
Ekman
S
S
Department of Pathology, SLU, Box 7028, SE-750 07 Uppsala, Sweden.
Skiöldebrand
E
E
Heinegård
D
D
Hultenby
K
K
D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002350:Carpus, Animal / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure*; D002358:Cartilage, Articular / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure*; D006734:Horse Diseases / Q000378:metabolism* / Q000473:pathology; D006736:Horses; D058574:Integrin-Binding Sialoprotein; D010003:Osteoarthritis / Q000378:metabolism / Q000473:pathology / Q000662:veterinary*; D012795:Sialoglycoproteins / Q000378:metabolism* / Q000648:ultrastructure
D015415:Biomarkers; D058574:Integrin-Binding Sialoprotein; D012795:Sialoglycoproteins