Microscopic characterisation of local strain field in healing tissue in the central third defect of mouse patellar tendon at early-phase of healing
Microscopic characterisation of local strain field in healing tissue in the central third defect of mouse patellar tendon at early-phase of healing
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DOI：
10.1016/j.jmbbm.2021.104702
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发表时间：
2021-08-06
影响因子：
3.9
通讯作者：
Matsumoto, Takeo
中科院分区：
文献类型：
--
作者：
Maeda, Eijiro;Kuroyanagi, Kaname;Matsumoto, Takeo
ABS T R A C T 肌腱表现出分层的胶原结构，其中更高级别的成分，例如胶原纤维和束，在宏观拉伸过程中被拉长、滑动和旋转。胶原纤维的这些机械行为在刺激肌腱细胞、施加拉伸、压缩和剪切变形方面发挥着重要作用。据推测，愈合肌腱组织中局部纤维行为的缺乏可能会导致对组织内细胞的机械刺激作用有限，从而导致再生肌腱中组织结构和功能的不完全恢复。因此，本研究旨在测量愈合肌腱组织中的微观应变场。在小鼠的髌腱中制造中央第三缺损，并在术后 3 周和 6 周通过拉伸测试、胶原纤维分析和使用共焦显微镜进行局部应变测量来检查缺损处的再生组织。与正常肌腱相比，3周时愈合的组织表现出明显较低的强度和紊乱的胶原纤维结构。 6周时这些特征与正常肌腱的特征仍然显着不同。此外，在4%组织应变下，愈合组织的局部剪切应变大小明显小于正常肌腱。局部应变场的差异可能反映在细胞核形状中，并且可能反映在肌腱变形期间施加到细胞的机械刺激量。因此，恢复愈合组织中正常的局部机械环境可能是肌腱损伤获得更好愈合结果的关键。
ABS T R A C T Tendons exhibit a hierarchical collagen structure, wherein higher-level components, such as collagen fibres and fascicles, are elongated, slid, and rotated during macroscopic stretching. These mechanical behaviours of collagen fibres play important roles in stimulating tenocytes, imposing stretching, compression, and shear deformation. It was hypothesised that a lack of local fibre behaviours in healing tendon tissue may result in a limited application of mechanical stimuli to cells within the tissue, leading to incomplete recovery of tissue structure and functions in regenerated tendons. Therefore, the present study aimed to measure the microscopic strain field in the healing tendon tissue. A central third defect was created in the patellar tendon of mice, and the regenerated tissue in the defect was examined by tensile testing, collagen fibre analysis, and local strain mea-surement using confocal microscopy at 3 and 6 weeks after surgery. Healing tissue at 3 weeks exhibited a significantly lower strength and disorganised collagen fibre structure compared with the normal tendon. These characteristics at 6 weeks remained significantly different from those of the normal tendon. Moreover, the magnitude of local shear strain in the healing tissue under 4% tissue strain was significantly smaller than that in the normal tendon. Differences in the local strain field may be reflected in the cell nuclear shape and possibly the amount of mechanical stimuli applied to the cells during tendon deformation. Accordingly, restoration of a normal local mechanical environment in the healing tissue may be key to a better healing outcome of tendon injury.