Authors: Sullivan Stasia N, Altmann Nadine N, Brokken Matthew T, Durgam Sushmitha S
Journal: Frontiers in veterinary science
Summary
# Editorial Summary Navicular disease remains a significant source of chronic lameness in horses, with deep digital flexor tendon (DDFT) degeneration and associated fibrocartilage changes playing a central role in its pathology. Sullivan and colleagues conducted an in-vitro investigation to establish whether methylprednisolone acetate (MPA)—a corticosteroid routinely delivered intrasynovially—might impair the biosynthetic capacity of DDFT cells, a concern that had never been directly examined. Using tendon cells harvested from five mature horses (aged 11–17 years), the researchers exposed three-dimensional cell aggregates to MPA at concentrations of 0, 0.05, and 0.5 mg/mL for 24 hours, then measured changes in gene expression related to tendon and cartilage matrix production, alongside quantifying glycosaminoglycan (GAG) and collagen synthesis and matrix metalloproteinase activity. The higher MPA dose (0.5 mg/mL) suppressed tendon-related gene expression, whilst both concentrations downregulated cartilage-related genes; however, neither dose altered actual matrix protein production or degradative enzyme activity within the timeframe tested. For practitioners, these findings suggest that short-term intrasynovial corticosteroid administration may have limited direct impact on DDFT matrix synthesis at physiological exposures, though the authors appropriately call for longer-term studies in inflammatory conditions to fully characterise safety and efficacy in clinical navicular disease.
Read the full abstract on PubMed
Practical Takeaways
- •While intrasynovial methylprednisolone reduces inflammation, it may suppress the tendon and cartilage cells' ability to produce matrix components—the long-term clinical significance of this requires further investigation
- •Current in-vitro evidence does not support concerns about corticosteroids preventing cell recovery at therapeutic doses, but real-world inflammatory conditions may produce different results
- •Until longer-term studies are completed, intrasynovial corticosteroids remain appropriate for navicular disease management, but clinicians should monitor for adequate healing response
Key Findings
- •Higher MPA concentration (0.5 mg/mL) significantly down-regulated tendon ECM-related genes after 24h treatment
- •Both MPA doses (0.05 and 0.5 mg/mL) significantly down-regulated cartilage ECM-related genes
- •MPA treatment did not affect total GAG content in DDFT-derived cells or culture medium compared to controls
- •No significant changes in collagen, MMP-3, or MMP-13 concentrations in culture medium with MPA treatment