HOX Gene Expressions in Cultured Articular and Nasal Equine Chondrocytes

SIMPLE SUMMARY: Once articular cartilage is damaged, it is unable to regain its original tissue integrity, which leads to osteoarthritis including degeneration of the joint, suffering and pain. In equine medicine there is no therapy available to repair joint defects. Hyaline cartilage of nasal septum shows a high basal collagen II expression, which may have a positive effect on damaged articular cartilage. Therefore, nasal septum could be a potential source for chondrocytes for autologous implantation in the future. ABSTRACT: Osteoarthritis the quality and span of life in horses. Previous studies focused on nasal cartilage as a possible source for autologous chondrocyte implantation (ACI) in cartilage defects in humans. “HOX gene-negative” nasal chondrocytes adapted articular HOX patterns after implantation into caprine joint defects and produced cartilage matrix proteins. We compared the HOX gene profile of equine chondrocytes of nasal septum, anterior and posterior fetlock to identify nasal cartilage as a potential source for ACI in horses. Cartilage was harvested from seven horses after death and derived chondrocytes were cultured in a monolayer to fourth subcultivation. HOX A3, D1, D8 and chondrocyte markers COL2 and SOX9 were analyzed with qPCR in chondrocytes of three different locations obtained during passage 0 and passage 2. HOX gene expression showed no significant differences between the locations but varied significantly between the horses. HOX genes and SOX9 remained stable during culturing. Cultured nasal chondrocytes may be a target for future research in cell-based regenerative therapies in equine osteoarthritis. The involvement of HOX genes in the high regenerative and adaptive potential of nasal chondrocytes observed in previous studies could not be confirmed.