Model of Disc Degeneration in Rat Tail Induced Through a Vascular Isolation of Vertebral Endplates

ABSTRACT

Back pain is a major health problem. The degenerative cascade of the spine begins in the intervertebral disc, due to an impairment in the blood supply through the vertebral endplates. Our objective was to develop a novel disc degeneration model based on these premises, akin to the process in humans, in contrast to other proposed models (puncture, enzyme injection, aberrant loads,…) Material and methods: 37 Sprague-Dawley rats, 2 arms: (a) histological (n = 17, one died), en- bloc sections, Van Gieson staining, (Nisimura-Mochida criteria) and also collagen VI staining (tissue oxidative stress), four animals were euthanized every 2 weeks (2-8); and (b) imaging (n = 20, six wound sloughs), MRI 9.4 Tesla protocol, sequential disc volumetric analysis (24 h-8 weeks) in all animals. Disc degeneration was induced by means of vascular isolation of tail discs endplates either from one side or both. Results: Isolation from both sides caused a progressive degeneration of the disc (p < 0.001 vs. controls), bigger than isolation from one side (p < 0.01 vs. both sides and p < 0.05 vs. controls), as rated by volumetric reduction; furthermore, tissue structural changes (Nisimura-Mochida) and collagen VI deposition confirmed these results. Conclusion: the model here described represents a novel and translational tool that reproduces the intervertebral disc degeneration in a similar way to that taking place in human beings.

Keywords::

• spine
• intervertebral disc
• degeneration
• MRI
• model
• vascular isolation
• translational

Acknowledgments

This study has been partially supported by grants from Instituto de Salud Carlos III (PI13/00292; PI14/01879). Furthermore, this study was also co-financed by the ERDF (European Regional Development Fund). Finally, T. Sobrino (CP12/03121) and F. Campos (CP14/00154) are recipients of a research contract from Miguel Servet Program of Instituto de Salud Carlos III. The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.

To both Prof. Forteza and Prof. Antunez, Chairs of Pathology, who graded the samples of the histological study.

To Ms. Ana Estany, Pharm. PhD., Epidemilogical Unit of the Universitary Hospitalary Complex of Santiago de Compostela, who helped in the statistical analysis of the MRI study.