Levels of Cytokines and Matrix Metalloproteinases 2 and 9 in the Synovial Fluid of Osteoarthritic Horses Treated With Pamidronate

• We evaluate the effect of pamidronate in healthy and with joint disease horses.
• Pamidronate significantly improved the condition of horses with osteoarthritis.
• Values of IL-6 and TNFα were similar with the control group at day 3 of treatment.
• MMP-9 activity was absent at day 10 and 21 of treatment.

The aim of this study was to evaluate the effect of pamidronate on the clinical score and the secretory profile of inflammatory biomarkers (interleukin [IL]-6, tumor necrosis factor alpha [TNF-α], matrix metalloproteinase [MMP]-2, and MMP-9) in the synovial fluid in clinically healthy horses and in horses with joint disease. Healthy horses and horses with joint symptoms were examined and subjected to a standardized clinical evaluation of the locomotor system. The clinical condition was evaluated by a global score. Matrix metalloproteinases 2 and 9 were measured by gel zymography. The concentration of cytokines (IL-6 and TNF-α) in synovial fluid was determined by enzyme linked immunosorbent assay (ELISA). Pamidronate treatment significantly improved the clinical condition of horses with osteoarthritis (OA). Values of IL-6 (pg/mL) were similar (ns) in the healthy control group (102.2 ± 26.94) and at day 3 of treated (TD) group (113.9 ± 18.33). Tumor necrosis factor alpha level, at day 3 of treatment, was significantly lower in TD groups than in untreated osteoarthritis. Treated group registered a fast increase in MMP-9 activity but till days 21 and 60 it was not detectable. No significant differences were found in the MMP-2 activity between groups. We concluded that treatment with pamidronate has a beneficial effect on the clinical score of horses with OA and can reduce proinflammatory cytokines (IL-6 and TNF-α) and MMP-9 at different stages after treatment.