Histopathology of the Intervertebral Disc of , a Fish Model of Accelerated Aging.

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. is an established model for accelerated aging that spontaneously develops spinal deformities. Although the bone properties of 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 .

Material And Methods: Intervertebral properties of healthy and deformed 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 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 . Further studies should investigate the utility of as a model for degenerative spine diseases.