Histopathology of the Intervertebral Disc of Nothobranchius furzeri, a Fish Model of Accelerated Aging

SIMPLE SUMMARY: Osteoarthritis is a common complex disease, which affects the whole joint and causes disability in millions of patients. Currently, there is no cure for this disease; there is only the possibility of symptomatic therapy. Due to this, animal models play an important role in further investigating the pathophysiology and developing therapeutic strategies. The turquoise killifish, Nothobranchius furzeri, is a well-known model for the investigation of the effects of fast aging, that spontaneously develops spinal deformities. The aim of this study was to investigate the characteristics of the intervertebral discs of healthy and deformed N. furzeri, which have never been described before. Our study shows age- and disease-related alterations in the vertebral discs of N. furzeri. ABSTRACT: Introduction: Osteoarthritis is a classical age-related disease, which affects millions of patients worldwide. To further understand the pathophysiology and to develop therapeutic strategies for this disease, animal models play a significant role. Nothobranchius furzeri is an established model for accelerated aging that spontaneously develops spinal deformities. Although the bone properties of N. furzeri are well described, characteristics of the intervertebral discs are still unknown. The aim of this study was to investigate the characteristics of the intervertebral discs of healthy and deformed N. furzeri. Material and Methods: Intervertebral properties of healthy and deformed N. furzeri were investigated in 8-, 12-, 18- and 21.5-week-old male fish of the GRZ strain. For histological evaluations the fish were decalcified, paraffin-embedded and stained with (1) hematoxylin and eosin, (2) toluidine blue and (3) alcian blue/picrosirius red. Results: 8-week-old and deformed N. furzeri showed spongy-like tissue containing vacuolated notochord cells and a beginning formation of fibrous tissue in the central area. Older healthy fish showed fibrous tissue in the central region and a spongy-like tissue in the peripheral region. Conclusion: Our study revealed age- and disease-related alterations of the vertebral discs in N. furzeri. Further studies should investigate the utility of N. furzeri as a model for degenerative spine diseases.