Matrix metalloproteinase activity in equine synovial fluid: influence of age, osteoarthritis, and osteochondrosis
- aDepartment of General and Large Animal Surgery, Faculty of Veterinary Medicine, Utrecht, the Netherlands, bGaubius Laboratory TNO Prevention and Health, Division of Vascular and Connective Tissue Research, Leiden, the Netherlands
- P A J Brama, Department of General and Large Animal Surgery, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 12, NL-3584 CM Utrecht, the Netherlands.
- Accepted 14 August 1998
Abstract
OBJECTIVE To investigate the influence of age, osteoarthritis (OA), and osteochondrosis (OC) on the matrix metalloproteinase (MMP) activity in the synovial fluid (SF) of equine joints.
METHODS SF was collected from normal and osteoarthritic metacarpophalangeal joints (normal: 14 adult, 28 juvenile; OA: 22 adult). And from normal and osteochondrotic tarsocrural joints (5 months: 11 normal, 8 OC; 11 months: 7 normal, 6 OC). Subsequently, overall MMP activity was measured.
RESULTS The level of active MMPs was almost twofold higher in SF from juvenile horses (age up to 11 months) than in SF from mature animals (4–30 years; p<0.001). In juvenile horses MMP activity was higher in 5 month old foals than in 11 month old foals (p<0.01). In adult horses MMP activity was independent of age. In OA joints the activity was nearly twice as high as in normal joints (p<0.001). In OC joints MMP activity was not significantly different from normal, age matched, control joints.
CONCLUSIONS MMP activity in SF from normal adult joints is not related to age. In juvenile joints MMP activity is significantly higher than activity in joints from adult animals. It is hypothesised that the gradual decrease in MMP activity with increasing age reflects the declining metabolic activity resulting from ceasing growth and the accompanying decrease in cartilage remodelling. The increased MMP activity in osteoarthritic joints most likely reflects matrix destruction. In osteochondrosis MMP mediated matrix degradation appears not to be different from normal joints.
