Department of Engineering, Faculty of Environment, Science and Economy, University of Exeter, Exeter, United Kingdom.
Department of Physics and Astronomy, Faculty of Environment, Science and Economy, University of Exeter, Exeter, United Kingdom.
J Biomech. 2024 Apr;167:112068. doi: 10.1016/j.jbiomech.2024.112068. Epub 2024 Mar 31.
Intervertebral disc (IVD) degeneration includes changes in tissue biomechanics, physical attributes, biochemical composition, disc microstructure, and cellularity, which can all affect the normal function of the IVD, and ultimately may lead to pain. The purpose of this research was to develop an in-vitro model of degeneration that includes the evaluation of physical, biomechanical, and structural parameters, and that does so over several load/recovery periods. Hyperphysiological loading was used as the degenerative initiator with three experimental groups employed using bovine coccygeal IVD specimens: Control; Single-Overload; and Double-Overload. An equilibrium stage comprising a static load followed by two load/recovery periods was followed by six further load/recovery periods. In the Control group all load/recovery periods were the same, comprising physiological cyclic loading. The overload groups differed in that hyperphysiological loading was applied during the 4th loading period (Single-Overload), or the 4th and 5th loading period (Double-Overload). Overloading led to a significant reduction in disc height compared to the Control group, which was not recovered in subsequent physiological load/recovery periods. However, there were no significant changes in stiffness. Overloading also led to significantly more microstructural damage compared to the Control group. Taking all outcome measures into account, the overload groups were evaluated as replicating clinically relevant aspects of moderate IVD degeneration. Further research into a potential dose-effect, and how more severe degeneration can be replicated would provide a model with the potential to evaluate new treatments and interventions for different stages of IVD degeneration.
椎间盘（IVD）退变包括组织生物力学、物理特性、生化组成、椎间盘微观结构和细胞成分的变化，这些变化都会影响 IVD 的正常功能，并最终可能导致疼痛。本研究的目的是开发一种退变的体外模型，该模型包括对物理、生物力学和结构参数的评估，并且可以在多个加载/恢复周期中进行。超生理负荷被用作退变的启动因素，使用牛尾骨 IVD 标本进行了三组实验：对照组、单次超负荷组和双次超负荷组。在平衡阶段，包括静态加载和两个加载/恢复周期，然后进行六个进一步的加载/恢复周期。在对照组中，所有加载/恢复周期都是相同的，包括生理循环加载。超负荷组的不同之处在于，在第 4 个加载周期（单次超负荷）或第 4 个和第 5 个加载周期（双次超负荷）施加超生理负荷。与对照组相比，超负荷导致椎间盘高度显著降低，并且在随后的生理加载/恢复周期中无法恢复。然而，刚度没有显著变化。与对照组相比，超负荷还导致更明显的微结构损伤。考虑到所有的结果指标，超负荷组被评估为复制了中度 IVD 退变的临床相关方面。进一步研究潜在的剂量效应以及如何复制更严重的退变，将为评估不同阶段的 IVD 退变的新治疗和干预措施提供一种有潜力的模型。
