Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.
Department of Engineering Science, University of Auckland, Auckland, New Zealand.
Biomech Model Mechanobiol. 2017 Oct;16(5):1729-1741. doi: 10.1007/s10237-017-0916-4. Epub 2017 May 18.
The NZ white rabbit is the animal of choice for much experimental work due to its muscular frame and similar response to human diseases, and is one of the few mammals that have had their genome sequenced. However, continuum-level computational models of rabbit muscle detailing fibre architecture are limited in the literature, especially the triceps surae complex (gastrocnemius, plantaris and soleus), which has similar biomechanics and translatable findings to the human. This study presents a geometrical model of the rabbit triceps surae informed with diffusion-weighted imaging (DWI)-based fibres. Passive rabbit-specific material properties are estimated using known muscle deformation inferred from magnetic resonance imaging data and dorsiflexion force measured with a custom-built rabbit rig and transducer. Muscle shape prediction is evaluated against a second rabbit. This study revealed that the triceps surae steady-state force post-rigor is close to post-mortem for small deformations but increases by a fixed ratio as the deformation increases and can be used to evaluate the passive behaviour of muscle. DWI fibre orientation significantly influences shape and mechanics during simulated computational muscle contraction. The presented triceps surae force and material properties may be used to inform the constitutive behaviour of continuum rabbit muscle models used to investigate pathology and musculotendon treatments that may be translated to the human condition.
新西兰白兔由于其肌肉结构和对人类疾病的相似反应，成为许多实验工作的首选动物，并且是少数几种基因组已测序的哺乳动物之一。然而，详细描述纤维结构的兔肌肉连续体水平计算模型在文献中有限，特别是三头肌复合物（比目鱼肌、跖肌和腓肠肌），其具有相似的生物力学和可转化的人类发现。本研究提出了一种基于扩散加权成像（DWI）纤维的兔三头肌几何模型。使用从磁共振成像数据推断出的已知肌肉变形和使用定制的兔架和换能器测量的背屈力来估计兔特有的被动材料特性。肌肉形状预测与第二只兔子进行了比较。本研究表明，三头肌在小变形后的僵硬后稳态力接近死后状态，但随着变形的增加，它会按固定比例增加，可用于评估肌肉的被动行为。DWI 纤维方向在模拟计算肌肉收缩过程中显著影响形状和力学。所提出的三头肌力和材料特性可用于为连续体兔肌肉模型的本构行为提供信息，这些模型用于研究可能转化为人类疾病的病理学和肌肉肌腱治疗。
