Leavey Alice, Richards Christopher T, Porro Laura B
Centre for Integrative Anatomy, Cell and Developmental Biology, University College London, Bloomsbury, London, UK.
Structure and Motion Laboratory, Royal Veterinary College-Camden Campus, Comparative Biomedical Sciences, London, UK.
J Morphol. 2025 Jan;286(1):e70016. doi: 10.1002/jmor.70016.
Muscle fibre architecture is an important aspect of anatomy to consider when estimating muscle properties. How fibre architecture varies across species specialising in different locomotor functions is not well understood in anurans, due to difficulties associated with fibre extraction in small animals using traditional methods. This paper presents the first digital analysis of fibre architecture in frogs using an automated fibre-tracking algorithm and contrast-enhanced µCT scans. We find differences in hindlimb muscle fibre architecture between frogs specialising in different locomotor modes, as well as examples of many-to-one mapping of form to function. The trade-off between fibre length and muscle physiological cross-sectional area, and therefore contractile speed, range of motion and muscle force output, differs significantly between jumpers and swimmers, but not walker-hoppers. Where species place on this functional spectrum of fibre architecture largely depends on the muscle being examined. There is also some evidence that fibre length may be adjusted to increase contractile speed without undertaking the metabolically expensive process of growing and maintaining larger muscles. Finally, we make a detailed outline of the remaining gaps in our understanding of anuran fibre architecture that can now be addressed with this valuable digital method in future research.
在评估肌肉特性时，肌肉纤维结构是解剖学中需要考虑的一个重要方面。由于使用传统方法从小动物身上提取纤维存在困难，在无尾两栖类动物中，对于专门从事不同运动功能的物种之间纤维结构如何变化，人们还了解得不够充分。本文首次使用自动纤维追踪算法和对比增强μCT扫描对青蛙的纤维结构进行了数字分析。我们发现，专门从事不同运动模式的青蛙后肢肌肉纤维结构存在差异，同时也发现了许多形式与功能一一对应的例子。纤维长度与肌肉生理横截面积之间的权衡，以及由此产生的收缩速度、运动范围和肌肉力量输出，在跳跃者和游泳者之间存在显著差异，但在步行跳跃者之间没有差异。物种在这种纤维结构功能谱上的位置很大程度上取决于所检查的肌肉。也有一些证据表明，纤维长度可能会被调整以提高收缩速度，而无需经历生长和维持更大肌肉这种代谢成本高昂的过程。最后，我们详细概述了目前在我们对无尾两栖类动物纤维结构的理解中仍然存在的空白，这些空白现在可以在未来的研究中通过这种有价值的数字方法来解决。
