Influence of an n-3 long-chain polyunsaturated fatty acid-enriched diet on experimentally induced synovitis in horses.

This research explored whether a diet enriched with n-3 long-chain polyunsaturated fatty acid (LCPUFA) could affect joint inflammation in horses. The study did not find any significant changes in synovial fluid biomarkers, however, there was a decrease in ADAMTS-4 mRNA expression in horses fed this diet, suggesting more research is needed.

Methodology

• Twelve mature, non-pregnant mares were randomly assigned to either a control diet (CONT) or an n-3 long-chain fatty acid-enriched treatment diet (N3FA) containing 40 g/day of n-3 LCPUFA for a period of 91 days.
• The researchers collected blood samples on days 0, 30, 60 and 90, and synovial fluid on days 0 and 90 processed them for lipid composition.
• On day 91, joint inflammation was induced using an intra-articular injection of recombinant equine IL-1beta (reIL-1β).
• Synovial fluid samples were collected again at post-injection hours (PIH) 0, 4, 8 and 24, analyzed for prostaglandin E2 (PGE2), matrix metalloproteinase (MMP) activity and routine cytology.
• The researchers also analyzed the synovium and articular cartilage samples for gene expressions of MMP 1, MMP 13, interleukin-1beta (IL-1β), COX-2, tumor necrosis factor-alpha, a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-4 and ADAMTS-5.

Results

• It was observed that a 90-day feeding period of n-3 LCPUFA increased serum phospholipid and synovial fluid lipid compositions of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) compared to the CONT horses.
• The reIL-1β injection caused an inflammatory response but the dietary treatment’s effect on synovial fluid PGE2 content and MMP activity was inconclusive.
• The synovial tissue collected from N3FA horses exhibited lower expression of ADAMTS-4 compared to those on a CONT diet.

Conclusion

• The research found no significant changes in synovial fluid biomarkers between dietary treatments, indicating that dietary n-3 LCPUFA supplementation did not significantly modify joint inflammation in horses.
• However, noticing the lower count of ADAMTS-4 mRNA expression in N3FA horses shows cause to further investigate the potential value of n-3 LCPUFA as joint therapy in horses.