Quantitative model for predicting lymph formation and muscle compressibility in skeletal muscle during contraction and stretch
Quantitative model for predicting lymph formation and muscle compressibility in skeletal muscle during contraction and stretch
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DOI：
10.1073/pnas.1206398109
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发表时间：
2012-06-05
影响因子：
11.1
通讯作者：
Weinbaum, Sheldon
中科院分区：
文献类型：
--
作者：
Causey, Laura;Cowin, Stephen C.;Weinbaum, Sheldon
尽管肌内膜和肌周空间内的血管和淋巴管在拉伸和收缩过程中直径和长度发生显着变化，但骨骼肌被广泛认为几乎不可压缩。事实证明，束束和间质之间的这些液体转移极其难以测量。在本文中，我们提出了一个基于空间填充六角束阵列的理论框架，以预测拉伸和收缩过程中血液和淋巴液进出肌肉肌内膜和肌束膜的位移。我们还使用该模型使用大鼠斜方肌的数据来量化束及其肌周间隙内血液和初始淋巴管（IL）的分布。每个束平均有 11 根肌纤维、0.4 对小动脉/小静脉和 0.2 个 IL 血管。该模型预测，收缩 20% 和拉伸 20% 时，肌内膜腔内的血容量分别增加 24% 和减少 22%。然而，肌内膜血容量的这些显着变化仅导致肌束横截面积发生约 2% 的变化。相比之下，对于 20% 的收缩和拉伸，整个肌肉分别偏离等容法 7% 和 6%，这主要归因于肌周间隙中发生的显着更大的血容量变化。这表明肌周间隙中的拱形血管提供了肌肉收缩和伸展过程中 IL 的填充和排空所需的主要泵送作用。
Skeletal muscle is widely perceived as nearly incompressible despite the fact that blood and lymphatic vessels within the endomysial and perimysial spaces undergo significant changes in diameter and length during stretch and contraction. These fluid shifts between fascicle and interstitial compartments have proved extremely difficult to measure. In this paper, we propose a theoretical framework based on a space-filling hexagonal fascicle array to provide predictions of the displacement of blood and lymph into and out of the muscle's endomysium and perimysium during stretch and contraction. We also use this model to quantify the distribution of blood and initial lymphatic (IL) vessels within a fascicle and its perimysial space using data for the rat spinotrapezius muscle. On average, there are 11 muscle fibers, 0.4 arteriole/venule pairs, and 0.2 IL vessels per fascicle. The model predicts that the blood volume in the endomysial space increases 24% and decreases 22% for a 20% contraction and stretch, respectively. However, these significant changes in blood volume in the endomysium produce a change of only similar to 2% in fascicle cross-sectional area. In contrast, the entire muscle deviates from isovolumetry by 7% and 6% for a 20% contraction and stretch, respectively, largely attributable to the significantly larger blood volume changes that occur in the perimysial space. This suggests that arcade blood vessels in the perimysial space provide the primary pumping action required for the filling and emptying of ILs during muscular contraction and stretch.