Induction of increased levels of proteoglycan fragments in synovial fluid (SF) and increased levels of stromelysin in cartilage, synovium and SF by intraarticular injection of canine monocyte conditioned medium into dogs.

OBJECTIVE

To study the effects of the intraarticular injection of canine monocyte conditioned medium (cMCM) into dogs on proteoglycan fragment and stromelysin levels in the joint.

METHODS

cMCM was injected intraarticularly into dogs, and the levels of proteoglycan fragments in synovial fluid (SF) as well as stromelysin levels in cartilage, synovium, and SF were assessed after 12 h.

RESULTS

There was a 4-fold increase of proteoglycan fragment levels and a 6-fold increase in stromelysin levels in SF, and a 4.4-fold increase in stromelysin levels in cartilage extracts. Elevated mRNA levels were detected in both synovium and cartilage. By immunofluorescence staining, stromelysin was localized in chondrocytes throughout the cartilage and in synovial cells.

CONCLUSION

Intraarticular injection of cMCM stimulated the expression of stromelysin mRNA and protein in cartilage and synovium and caused marked increases in stromelysin protein and proteoglycan fragment levels in SF.