Conserved mammalian muscle mechanics during eccentric contractions
Conserved mammalian muscle mechanics during eccentric contractions
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DOI：
10.1113/jp285549
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发表时间：
2024-02-24
影响因子：
5.5
通讯作者：
Askew，Graham N.
中科院分区：
文献类型：
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作者：
Kissane，Roger W. P.;Askew，Graham N.
骨骼肌具有广泛的生物力学功能，包括发电和能量吸收。这些作用是由力-速度关系支撑的，力-速度关系包括两个不同的组成部分：同心和偏心的力-速度关系。同心成分已经在具有不同肌肉特性的各种肌肉中得到了广泛的研究。然而，到目前为止，在准确描述具有不同肌肉特性的哺乳动物肌肉中的偏心力-速度关系方面进展甚微。因此，这种肌肉行为的数学模型是基于一种鲜为人知的现象。在这里，我们提出了一个全面的评估四种不同生物力学功能的哺乳动物肌肉(比目鱼肌、指长伸肌、隔肌和二腹肌)的向心力-速度和偏心力-速度关系，跨越三个数量级的身体质量(小鼠、大鼠和兔子)。力-速度关系用同心分量的双曲线-线性方程和偏心分量的双曲线方程来表征，同时测量了力发展的两个阶段的力发展速度与偏心拉长速度的关系。我们证明，尽管偏心力-速度关系的曲率和平台高度不同，但在所研究的四个肌肉中，在等速加长坡道期间的力-时间响应的两个阶段相对于加长速度的相对力发展速率是一致的。我们的数据支持这样的假设，即这种关系依赖于跨桥和肌动蛋白的激活。哺乳动物肌肉的偏心力-速度关系的山型肌肉骨骼模型应该包括这种双相力响应。关键点骨骼肌产生机械功和吸收能量的能力由力-速度关系支撑。尽管80多年前就发现了延长(偏心)力-速度关系，但还没有进行全面的研究来表征这种关系。我们表明，在活跃的肌肉延长过程中看到的双相力响应在哺乳动物骨骼肌质量的三个数量级上是保守的。使用Titin小缺失的小鼠，与传统的双曲线拟合相比，肌肉拉伸过程中的力发展速率可能是描述偏心性肌肉收缩过程中所经历的力的更可靠的方法，并且可以作为力-速度特性的新的预测因子，可以更好地为山型肌肉骨骼模型提供信息并评估病理生理重构。
AbstractSkeletal muscle has a broad range of biomechanical functions, including power generation and energy absorption. These roles are underpinned by the force–velocity relationship, which comprises two distinct components: a concentric and an eccentric force–velocity relationship. The concentric component has been extensively studied across a wide range of muscles with different muscle properties. However, to date, little progress has been made in accurately characterising the eccentric force–velocity relationship in mammalian muscle with varying muscle properties. Consequently, mathematical models of this muscle behaviour are based on a poorly understood phenomenon. Here, we present a comprehensive assessment of the concentric force–velocity and eccentric force–velocity relationships of four mammalian muscles (soleus, extensor digitorum longus, diaphragm and digastric) with varying biomechanical functions, spanning three orders of magnitude in body mass (mouse, rat and rabbits). The force–velocity relationship was characterised using a hyperbolic‐linear equation for the concentric component a hyperbolic equation for the eccentric component, at the same time as measuring the rate of force development in the two phases of force development in relation to eccentric lengthening velocity. We demonstrate that, despite differences in the curvature and plateau height of the eccentric force–velocity relationship, the rates of relative force development were consistent for the two phases of the force–time response during isovelocity lengthening ramps, in relation to lengthening velocity, in the four muscles studied. Our data support the hypothesis that this relationship depends on cross‐bridge and titin activation. Hill‐type musculoskeletal models of the eccentric force–velocity relationship for mammalian muscles should incorporate this biphasic force response.Key pointsThe capacity of skeletal muscle to generate mechanical work and absorb energy is underpinned by the force–velocity relationship.Despite identification of the lengthening (eccentric) force–velocity relationship over 80 years ago, no comprehensive study has been undertaken to characterise this relationship in skeletal muscle.We show that the biphasic force response seen during active muscle lengthening is conserved over three orders of magnitude of mammalian skeletal muscle mass.Using mice with a small deletion in titin, we show that part of this biphasic force profile in response to muscle lengthening is reliant on normal titin activation.The rate of force development during muscle stretch may be a more reliable way to describe the forces experienced during eccentric muscle contractions compared to the traditional hyperbolic curve fitting, and functions as a novel predictor of force–velocity characteristics that may be used to better inform hill‐type musculoskeletal models and assess pathophysiological remodelling.