Matrix metallo-proteinases (MMP), present in most biological fluids, appear to be implicated in numerous physiologic and pathologic processes like embryogenesis, tissue remodelling, cancer, osteo-articular diseases etc. The aim of this study was to measure MMP2 and MMP9 activities in synovial fluid in different joints of healthy horses.

Synovial fluid from carpal, tarsal and metacarpo-phalangeal (MP) joints of eight clinically healthy horses have been collected by arthrocenthesis immediately post mortem. Samples were analysed by an electrophoretic method with a pre-incubation of 1 h at 37°C before migration and an incubation of 48 h at 37°C after migration. After coloration, gels were scanned and spots of lyses were measured.

Mean MMP2 and MMP9 activities (in Arbitrary Units of Lysis) in three different joints

For MMP2, we observed that activity in MP joints was significantly higher that in tarsal joints. MMP2 activity detected in carpal joint was intermediate. For MMP9, we observed a similar profile although the differences between joints did not reach significance.

It appears thus that synovial fluid MMP activity varies between joints of healthy horses. Further studies are necessary to confirm these preliminary findings by investigating variation factors like age, weight, breed, exercise and nutrition status.