Development of a standardized histopathology scoring system for intervertebral disc degeneration in rat models: An initiative of the ORS spine section
Résumé
Background:Rats are a widely accepted preclinical model for evaluating inter-vertebral disc (IVD) degeneration and regeneration. IVD morphology is commonlyassessed using histology, which forms the foundation for quantifying the state of IVDdegeneration. IVD degeneration severity is evaluated using different grading systemsthat focus on distinct degenerative features. A standard grading system would facili-tate more accurate comparison across laboratories and more robust comparisons ofdifferent models and interventions.Aims:This study aimed to develop a histology grading system to quantify IVD degen-eration for different rat models. Materials & Methods:This study involved a literature review, a survey of experts inthe field, and a validation study using 25 slides that were scored by 15 graders fromdifferent international institutes to determine inter- and intra-rater reliability.Results:A new IVD degeneration grading system was established and it consists ofeight significant degenerative features, including nucleus pulposus (NP) shape, NParea, NP cell number, NP cell morphology, annulus fibrosus (AF) lamellar organization,AF tears/fissures/disruptions, NP-AF border appearance, as well as endplate disrup-tions/microfractures and osteophyte/ossification. The validation study indicated thissystem was easily adopted, and able to discern different severities of degenerativechanges from different rat IVD degeneration models with high reproducibility forboth experienced and inexperienced graders. In addition, a widely-accepted protocolfor histological preparation of rat IVD samples based on the survey findings includeparaffin embedding, sagittal orientation, section thickness < 10μm, and staining usingH&E and/or SO/FG to facilitate comparison across laboratories.Conclusion:The proposed histological preparation protocol and grading system pro-vide a platform for more precise comparisons and more robust evaluation of rat IVDdegeneration models and interventions across laboratories.
Origine : Fichiers éditeurs autorisés sur une archive ouverte