Department of Orthodontics, Stomatological Hospital of Chongqing Medical University, Chongqing, China.
Chongqing Key Laboratory of Oral Disease and Biomedical Sciences, Stomatological Hospital of Chongqing Medical University, Chongqing, China.
Ann N Y Acad Sci. 2021 Nov;1503(1):72-87. doi: 10.1111/nyas.14606. Epub 2021 May 7.
Overloading stress-induced condylar cartilage degeneration acts as the main pathologic change in temporomandibular joint osteoarthritis (TMJ-OA). However, the progression of degeneration and the ability for self-repair remain poorly understood. Here, we explored the progression of cartilage degeneration by dividing pathological stages using a steady mouth-opening mouse model. Then, we observed changes of cartilage by removing the loading at different stages to test the potential self-repair after degeneration induced. Three-dimensional confocal microscopy combined with histology and micro-CT scanning was applied to examine TMJ at different stages of degeneration before and after self-repair. We found the cartilage underwent progressive and thorough degeneration as the overloading stress developed. During the initial adaptation stage, robust proliferation of posteromedial cartilage began at the area of direct loading. Subsequently, widespread chondrocyte apoptosis was found, followed by new chondrocyte proliferation in aggregates with matrix degradation and subchondral bone catabolism. Finally, with cartilage surface damage, the degeneration reached a point where the lesion could not be reversed by self-repair. While the cartilage nearly returned to normal when the interference was removed within 5 days. These results suggested overloading force induces a pathological process of successive degeneration in TMJ cartilage, which can be reversed by self-repair at early stages.
加载压力诱导的髁突软骨退变是颞下颌关节骨关节炎（TMJ-OA）的主要病理变化。然而，退变的进展和自我修复能力仍知之甚少。在这里，我们通过使用稳定张口的小鼠模型将病理阶段进行划分，从而探索软骨退变的进展。然后，我们在不同阶段去除负荷以观察退变后软骨的潜在自我修复能力。三维共聚焦显微镜结合组织学和微 CT 扫描用于检查退变前后不同阶段的 TMJ。我们发现随着加载压力的增加，软骨经历了进行性和彻底的退变。在初始适应阶段，直接加载区域的髁突后内侧软骨开始大量增殖。随后，广泛的软骨细胞凋亡，随后在基质降解和软骨下骨代谢的聚集中有新的软骨细胞增殖。最后，由于软骨表面损伤，退变达到了自我修复无法逆转的程度。然而，当在 5 天内去除干扰时，软骨几乎恢复正常。这些结果表明，加载力在 TMJ 软骨中诱导了一个连续退变的病理过程，在早期阶段可以通过自我修复来逆转。
