Revealing the Therapeutic Potential of Muscle-Derived Mesenchymal Stem/Stromal Cells: An In Vitro Model for Equine Laminitis Based on Activated Neutrophils, Anoxia–Reoxygenation, and Myeloperoxidase

Laminitis in horses is a crippling condition marked by the deterioration of the dermal-epidermal interface, leading to intense lameness and discomfort, often necessitating euthanasia. This study aimed to establish an in vitro model of laminitis using a continuous keratinocyte cell line exposed to anoxia-reoxygenation and an activated neutrophil supernatant. A significant decrease in the keratinocytes' metabolism was noted during the reoxygenation period, indicative of cellular stress. Adding muscle-derived mesenchymal stem/stromal cells during the reoxygenation demonstrated a protective effect, restoring the keratinocytes' metabolic activity. Moreover, the incubation of the keratinocytes with either an activated neutrophil supernatant or myeloperoxidase alone induced increased keratinocyte myeloperoxidase activity, which was modulated by stem cells. These findings underscore the potential of muscle-derived mesenchymal stem/stromal cells in mitigating inflammation and restoring keratinocyte metabolism, offering insights for future cell therapy research in laminitis treatment.