Institute Pasteur Cenci-Bolognetti, Department of Histology and Medical Embryology, CE-BEMM, Sapienza University of Rome, 00161 Rome, Italy.
J Biomech. 2009 Oct 16;42(14):2243-8. doi: 10.1016/j.jbiomech.2009.06.041. Epub 2009 Aug 7.
Muscular dystrophy is a genetic disorder of skeletal muscle characterized by progressive muscle weakness. Here we assessed whether muscle wasting affects cell viability and mechanical properties of extensor digitorum longus (EDL) and of tibialis anterior (TA) tendons from mdx dystrophic mice compared to wild type (WT) mice. mdx mice represent the classical animal model for human Duchenne muscular dystrophy, and show several signs of the pathology, including a decrease in specific force and an increase of fibrotic index. Cell viability of tendons was evaluated by histological analysis, and viscoelastic properties have been assessed by a rapid measurement protocol that allowed us to compute, at the same time, tissue complex compliance for all the frequencies of interest. Confocal microscopy and mechanical properties measurements revealed that mdx tendons, compared to WT ones, have an increase in the number of dead cells and a significant reduction in tissue elasticity for all the frequencies that were tested. These findings indicate a reduced quality of the tissue. Moreover, mdx tendons have an increase in the viscous response, indicating that during dynamic loading, they dissipate more energy compared to WT. Our results demonstrate that muscular dystrophy involves not only muscle wasting, but also alteration in the viscoelastic properties of tendons, suggesting a paracrine effect of altered skeletal muscle on tendinous tissue.
肌肉萎缩症是一种骨骼肌的遗传性疾病，其特征是进行性肌肉无力。在这里，我们评估了与野生型（WT）相比，肌肉萎缩是否会影响 mdx 肌营养不良症小鼠的伸趾长肌（EDL）和胫骨前肌（TA）肌腱的细胞活力和力学特性。mdx 小鼠是人类杜氏肌营养不良症的经典动物模型，表现出多种病理迹象，包括特定力量下降和纤维化指数增加。通过组织学分析评估肌腱的细胞活力，并通过快速测量方案评估粘弹性特性，该方案允许我们同时计算出所有感兴趣频率的组织复弹性。共聚焦显微镜和力学性能测量显示，与 WT 相比，mdx 肌腱的死亡细胞数量增加，并且在所有测试的频率下组织弹性显著降低。这些发现表明组织质量下降。此外，mdx 肌腱的粘性响应增加，表明与 WT 相比，它们在动态加载过程中会消耗更多的能量。我们的结果表明，肌肉萎缩症不仅涉及肌肉萎缩，还涉及肌腱粘弹性特性的改变，这表明改变的骨骼肌对腱组织具有旁分泌作用。
