The temporomandibular joint (TMJ) disc is mainly composed of collagen, with its arrangement responding to efficient stress distribution. However, microstructural and micromechanical transformations of the TMJ disc under resting, functional, and pathological conditions remain unclear. To address this, our study presents a high-resolution microstructural and mechanical atlas of the porcine TMJ disc. First, the naive microstructure and mechanical properties were investigated in porcine TMJ discs (resting and functional conditions). Subsequently, the perforation and tear models (pathological conditions) were compared. Following this, a rabbit model of anterior disc displacement (abnormal stress) was studied. Results show diverse microstructures and mechanical properties at the nanometer to micrometer scale. In the functional state, gradual unfolding of the crimping cycle in secondary and tertiary structures leads to D-cycle prolongation in the primary structure, causing tissue failure. Pathological conditions lead to stress concentration near the injury site due to collagen interfibrillar traffic patterns, resulting in earlier damage manifestation. Additionally, the abnormal stress model shows collagen damage initiating at the primary structure and extending to the superstructure over time. These findings highlight collagen’s various roles in different pathophysiological states. Our study offers valuable insights into TMJ disc function and dysfunction, aiding the development of diagnostic and therapeutic strategies for TMJ disorders, as well as providing guidance for the design of structural biomimetic materials.

中文翻译：

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颞下颌关节盘的显微结构、显微机械图谱

颞下颌关节（TMJ）盘主要由胶原蛋白组成，其排列响应有效的应力分布。然而，颞下颌关节盘在静息、功能和病理条件下的微观结构和微观机械变化仍不清楚。为了解决这个问题，我们的研究提出了猪颞下颌关节盘的高分辨率微观结构和力学图谱。首先，研究了猪 TMJ 盘的原始微观结构和机械性能（静止和功能条件）。随后，对穿孔和撕裂模型（病理状况）进行比较。随后，研究了椎间盘前移（异常应力）的兔模型。结果显示纳米到微米尺度上的不同微观结构和机械性能。在功能状态下，二级和三级结构中卷曲周期的逐渐展开导致一级结构中的D周期延长，导致组织衰竭。由于胶原纤维间的交通模式，病理条件导致损伤部位附近的应力集中，导致早期损伤表现。此外，异常应力模型显示胶原蛋白损伤从主要结构开始，并随着时间的推移延伸到上部结构。这些发现强调了胶原蛋白在不同病理生理状态中的不同作用。我们的研究为 TMJ 椎间盘功能和功能障碍提供了宝贵的见解，有助于开发 TMJ 疾病的诊断和治疗策略，并为结构仿生材料的设计提供指导。