Lai Alon, Gansau Jennifer, Gullbrand Sarah E, Crowley James, Cunha Carla, Dudli Stefan, Engiles Julie B, Fusellier Marion, Goncalves Raquel M, Nakashima Daisuke, Okewunmi Jeffrey, Pelletier Matthew, Presciutti Steven M, Schol Jordy, Takeoka Yoshiki, Yang Sidong, Yurube Takashi, Zhang Yejia, Iatridis James C
Leni and Peter W. May Department of Orthopaedics Icahn School of Medicine at Mount Sinai New York New York USA.
McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery Perelman School of Medicine University of Pennsylvania Philadelphia Pennsylvania USA.
JOR Spine. 2021 May 26;4(2):e1150. doi: 10.1002/jsp2.1150. eCollection 2021 Jun.
Rats are a widely accepted preclinical model for evaluating intervertebral disc (IVD) degeneration and regeneration. IVD morphology is commonly assessed using histology, which forms the foundation for quantifying the state of IVD degeneration. IVD degeneration severity is evaluated using different grading systems that focus on distinct degenerative features. A standard grading system would facilitate more accurate comparison across laboratories and more robust comparisons of different models and interventions.
This study aimed to develop a histology grading system to quantify IVD degeneration for different rat models.
MATERIALS & METHODS: This study involved a literature review, a survey of experts in the field, and a validation study using 25 slides that were scored by 15 graders from different international institutes to determine inter- and intra-rater reliability.
A new IVD degeneration grading system was established and it consists of eight significant degenerative features, including nucleus pulposus (NP) shape, NP area, NP cell number, NP cell morphology, annulus fibrosus (AF) lamellar organization, AF tears/fissures/disruptions, NP-AF border appearance, as well as endplate disruptions/microfractures and osteophyte/ossification. The validation study indicated this system was easily adopted, and able to discern different severities of degenerative changes from different rat IVD degeneration models with high reproducibility for both experienced and inexperienced graders. In addition, a widely-accepted protocol for histological preparation of rat IVD samples based on the survey findings include paraffin embedding, sagittal orientation, section thickness < 10 μm, and staining using H&E and/or SO/FG to facilitate comparison across laboratories.
The proposed histological preparation protocol and grading system provide a platform for more precise comparisons and more robust evaluation of rat IVD degeneration models and interventions across laboratories.
大鼠是评估椎间盘退变和再生的广泛接受的临床前模型。椎间盘形态通常使用组织学进行评估，这构成了量化椎间盘退变状态的基础。使用关注不同退变特征的不同分级系统来评估椎间盘退变的严重程度。一个标准的分级系统将有助于跨实验室进行更准确的比较，以及对不同模型和干预措施进行更可靠的比较。
本研究旨在开发一种组织学分级系统，以量化不同大鼠模型的椎间盘退变情况。
本研究包括文献综述、该领域专家调查以及一项验证研究，使用来自不同国际机构的15名评分者对25张切片进行评分，以确定评分者间和评分者内的可靠性。
建立了一种新的椎间盘退变分级系统，它由八个重要的退变特征组成，包括髓核（NP）形状、NP面积、NP细胞数量、NP细胞形态、纤维环（AF）层状结构、AF撕裂/裂隙/中断、NP-AF边界外观，以及终板中断/微骨折和骨赘/骨化。验证研究表明，该系统易于采用，并且能够区分来自不同大鼠椎间盘退变模型的不同严重程度的退变变化，对于有经验和无经验的评分者都具有高重现性。此外，基于调查结果，一种广泛接受的大鼠椎间盘样本组织学制备方案包括石蜡包埋、矢状位取向、切片厚度<10μm，以及使用苏木精和伊红（H&E）和/或番红固绿（SO/FG）染色，以促进跨实验室比较。
所提出的组织学制备方案和分级系统为跨实验室更精确地比较和更可靠地评估大鼠椎间盘退变模型及干预措施提供了一个平台。
