HOX Gene Expressions in Cultured Articular and Nasal Equine Chondrocytes.
Authors: Storch Christiane, Fuhrmann Herbert, Schoeniger Axel
Journal: Animals : an open access journal from MDPI
Summary
Osteoarthritis substantially impacts equine longevity and quality of life, making effective cartilage repair strategies a priority for practitioners managing joint disease. This work examined whether nasal septal cartilage could serve as a donor source for autologous chondrocyte implantation (ACI) in horses by comparing HOX gene expression profiles—genes known to regulate developmental patterning and cellular differentiation—across nasal, anterior fetlock, and posterior fetlock chondrocytes harvested from seven horses and cultured through passage 2. Contrary to previous findings in other species suggesting nasal chondrocytes possess unique regenerative properties linked to HOX gene activity, the researchers found no significant differences in HOX A3, D1, and D8 expression between cartilage locations, though expression did vary notably between individual horses; critically, both HOX genes and chondrocyte identity markers (COL2 and SOX9) remained stable during in vitro culture. These results suggest that whilst nasal chondrocytes remain a practical cell source for equine ACI—avoiding the morbidity of harvesting from weight-bearing joints—their therapeutic advantage does not appear to stem from distinctive HOX gene profiles, implying that other cellular or biochemical properties warrant investigation. Clinically, this supports further development of nasal cartilage harvesting protocols for regenerative therapies in equine joint disease, though practitioners should recognise that chondrocyte source selection may need to balance factors beyond genetic programming, such as cell yield, viability, and the local microenvironment of the recipient defect.
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Practical Takeaways
- •Nasal cartilage remains a viable cell source for autologous chondrocyte implantation in horses, as cultured nasal chondrocytes maintain chondrocyte markers during expansion
- •Individual horse variability in HOX expression is more significant than anatomical location, suggesting donor screening may be important for cell-based cartilage repair
- •The adaptive capacity of nasal chondrocytes observed in other species may operate through mechanisms other than HOX gene regulation, warranting further investigation
Key Findings
- •HOX gene expression (A3, D1, D8) showed no significant differences between nasal septum and fetlock chondrocytes across seven horses
- •HOX genes and SOX9 remained stable during culture passage 0 to passage 2
- •Gene expression patterns varied significantly between individual horses rather than by cartilage location
- •The regenerative potential of nasal chondrocytes could not be explained by differential HOX gene expression patterns