An experimentally induced osteoarthritis model in horses performed on both metacarpophalangeal and metatarsophalangeal joints: Technical, clinical, imaging, biochemical, macroscopic and microscopic characterization.
Authors: Bertoni Lélia, Jacquet-Guibon Sandrine, Branly Thomas, Legendre Florence, Desancé Mélanie, Mespoulhes Céline, Melin Martine, Hartmann Daniel-Jean, Schmutz Amandine, Denoix Jean-Marie, Galéra Philippe, Demoor Magali, Audigié Fabrice
Journal: PloS one
Summary
# Editorial Summary Researchers developed a refined experimental osteoarthritis model that induces lesions in all four fetlock joints of the same horse, rather than the traditional single-joint approach, thereby reducing animal numbers whilst maintaining statistical rigour through within-animal replication. Eight horses underwent controlled intra-articular injection to both metacarpophalangeal and metatarsophalangeal joints, with lesion progression monitored over 12 weeks using clinical assessment, radiography, ultrasonography, MRI, synovial fluid biochemistry, and post-mortem histology and gross pathology. The procedure was well tolerated across all animals, successfully producing mild osteoarthritis changes with minimal inter-individual variability—a notable exception being slightly higher synovial effusion in hind versus front fetlocks and marginally higher radiographic scores on the left side. This standardised, reproducible model represents a significant advancement for pre-clinical efficacy testing of emerging therapies, offering equine professionals a more ethically sound framework for translational research whilst providing data directly relevant to naturally occurring disease in working horses. The cartilage composition and biomechanical properties of equine joints closely mirror human physiology, positioning this model as a valuable bridge between in vitro studies and clinical application in both equine and human medicine.
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Practical Takeaways
- •This refined experimental model reduces the number of horses needed for osteoarthritis treatment studies by inducing disease in all 4 fetlock joints simultaneously, improving both ethics and cost-effectiveness of equine research
- •The consistency of lesion development across horses and limbs (except minor hind/left differences) makes this a reliable platform for testing new osteoarthritis therapies before clinical application
- •Farriers and veterinarians should understand that translational osteoarthritis research using horses is increasingly efficient and applicable to human medicine, potentially accelerating development of treatments beneficial to both species
Key Findings
- •Bilateral induction of mild osteoarthritis in all 4 fetlock joints of the same horse was feasible and well-tolerated across 8 horses
- •No significant differences in osteoarthritis progression between individual horses or between different limbs except for higher synovial effusion in hind fetlocks
- •Left fetlocks showed higher radiographic scores compared to right fetlocks, indicating minor laterality differences
- •The model successfully reduced animal numbers and individual variability while maintaining reliable characterization of osteoarthritis-associated changes over 12 weeks