Dhiman Manmeet S, Salaam Mohammed A, Bader Taylor J, Nicholls Fred, Jacobs W Bradley, Thomas Kenneth C, Bouchard Jacques, Salo Paul T, Hart David A, Swamy Ganesh, Duncan Neil A
McCaig Institute for Bone and Joint Health University of Calgary Calgary Alberta Canada.
Department of Biomedical Engineering University of Calgary Calgary Alberta Canada.
JOR Spine. 2025 May 14;8(2):e70067. doi: 10.1002/jsp2.70067. eCollection 2025 Jun.
Disc degeneration (DD) is accompanied by biomechanical changes in the intervertebral discs. The lamellae of the annulus fibrosus (AF) are interconnected through the interlamellar matrix (ILM). The ILM contains interlamellar cross-bridges, connecting the lamellae radially in three dimensions. Weakening of the ILM and the cross-bridges could contribute to delamination between the lamellae, reducing their ability to resist loads and thus contributing to loss of AF integrity associated with the development and progression of degeneration. The objective of the present study was to quantify the differences in interlamellar mechanical properties of fresh AF samples from surgical DD individuals compared to AF samples from non-DD donors.
An interlamellar peel test was performed on fresh AF tissue collected from DD surgeries ( = 36) and non-DD organ donors ( = 13). The tissue was peeled at 0.5 mm/s until complete separation. Interlamellar mechanical properties were calculated from the force-displacement curve.
Samples from DD individuals had lower Peel Stiffness ( = 0.001), Peel Strength ( = 0.001), Peel Toughness ( = 0.0009), and Standard Deviation of the Peel Stress ( = 0.02) compared to the tissue from non-DD organ donors. Age had moderate negative correlations with Peel Stiffness ( = -0.59), Peel Strength ( = -0.66), and Peel Toughness ( = -0.69) for non-DD samples only.
The mechanical integrity of the ILM was determined to be lower in surgical DD individuals compared to non-DD donors. Aging alone may not have affected the results, and rather, loss of the integrity of ILM during disease progression appeared to have significantly contributed to the differences observed. This study provides new mechanical insights into the delamination often observed in the AF of surgical DD individuals. Future biochemical and immunolocalization studies, integrated with mechanical data, will aim to understand the role of collagen and elastin structure and composition in the decreased mechanical integrity of affected tissues.
椎间盘退变（DD）伴随着椎间盘的生物力学变化。纤维环（AF）的板层通过层间基质（ILM）相互连接。ILM包含层间交叉桥，在三维空间中径向连接各板层。ILM和交叉桥的弱化可能导致板层间分层，降低其抵抗负荷的能力，从而导致与退变发展和进展相关的AF完整性丧失。本研究的目的是量化手术DD个体新鲜AF样本与非DD供体AF样本层间力学性能的差异。
对从DD手术（n = 36）和非DD器官供体（n = 13）收集的新鲜AF组织进行层间剥离试验。组织以0.5 mm/s的速度剥离直至完全分离。根据力-位移曲线计算层间力学性能。
与非DD器官供体的组织相比，DD个体的样本具有更低的剥离刚度（P = 0.001）、剥离强度（P = 0.001）、剥离韧性（P = 0.0009）和剥离应力标准差（P = 0.02）。仅对于非DD样本，年龄与剥离刚度（r = -0.59）、剥离强度（r = -0.66）和剥离韧性（r = -0.69）呈中度负相关。
与非DD供体相比，手术DD个体的ILM机械完整性较低。单独的衰老可能并未影响结果，相反，疾病进展过程中ILM完整性的丧失似乎对观察到的差异有显著贡献。本研究为手术DD个体AF中经常观察到的分层提供了新的力学见解。未来结合力学数据的生化和免疫定位研究将旨在了解胶原蛋白和弹性蛋白结构及组成在受影响组织机械完整性降低中的作用。
