Institute of Orthopaedic Research and Biomechanics, Trauma Research Centre, Ulm University, Helmholtzstraße 14, 89081, Ulm, Germany.
Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, R. Alfredo Allen, 4200-135, Porto, Portugal.
Eur Spine J. 2019 May;28(5):922-933. doi: 10.1007/s00586-019-05901-w. Epub 2019 Jan 28.
PURPOSE: The pathomechanism of annulus fibrosus (AF) failure is still unknown. We hypothesise that mechanical overload and an inflammatory microenvironment contribute to AF structural weakening. Therefore, the objective of this study was to investigate the influence of these factors on the AF, particularly the translamellar bridging network (TLBN) which connects the AF lamellae. METHODS: A bovine AF organ culture (AF-OC) model of standardised AF rings was used to study the individual and combined effects of cyclic tensile strain (CTS) and IL-1β (1 ng/mL) culture medium supplementation. AF-OCs were analysed for PGE production (ELISA) and deposition of IL-6, COX-2, fibrillin, and MMP3 in the tissue (immunohistochemistry, IHC). The mechanical strength of the TLBN was evaluated using a peel test to measure the strength required to separate an AF segment along a lamellar bound. RESULTS: The combination of CTS + IL-1β led to a significant increase in PGE production compared to Control (p < 0.01). IHC evaluations showed that the CTS + IL-1β group exhibited higher production of COX-2 and MMP3 within the TLBN regions compared to the adjacent lamellae and a significant increase in IL-6 ratio compared to Control (p < 0.05). A significant decrease in the annular peel strength was observed in the CTS + IL1β group compared to Control (p < 0.05). CONCLUSION: Our findings suggest that CTS and IL-1β act synergistically to increase pro-inflammatory and catabolic molecules within the AF, particularly the TLBN, leading to a weakening of the tissue. This standardised model enables the investigation of AF/TLBN structure-function relationship and is a platform to test AF-focused therapeutics. These slides can be retrieved under Electronic Supplementary Material.
目的:纤维环(AF)破裂的病理机制尚不清楚。我们假设机械性过载和炎症微环境导致 AF 结构减弱。因此,本研究旨在探讨这些因素对 AF 的影响,特别是连接 AF 板层的跨板层桥接网络(TLBN)。
方法:使用标准化 AF 环的牛 AF 器官培养(AF-OC)模型研究循环拉伸应变(CTS)和 IL-1β(1ng/mL)培养基补充的单独和联合作用。通过 ELISA 检测 PGE 产生,免疫组织化学(IHC)检测组织中 IL-6、COX-2、原纤维蛋白和 MMP3 的沉积。使用剥离试验评估 TLBN 的机械强度,以测量沿板层边界分离 AF 段所需的强度。
结果:与对照组相比,CTS+IL-1β 联合作用导致 PGE 产生显著增加(p<0.01)。IHC 评估显示,与相邻板层相比,CTS+IL-1β 组在 TLBN 区域内 COX-2 和 MMP3 的产生更高,与对照组相比,IL-6 比值显著增加(p<0.05)。与对照组相比,CTS+IL1β 组的环形剥离强度显著降低(p<0.05)。
结论:我们的发现表明,CTS 和 IL-1β 协同作用增加了 AF 中促炎和分解代谢分子,特别是 TLBN,导致组织减弱。该标准化模型可用于研究 AF/TLBN 结构-功能关系,并为 AF 特异性治疗的测试提供平台。这些幻灯片可以在电子补充材料中检索到。
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