Model analysis of the relationship between intracellular PO2 and energy demand in skeletal muscle.
Model analysis of the relationship between intracellular PO2 and energy demand in skeletal muscle.
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细胞内 PO2 与骨骼肌能量需求关系的模型分析。
DOI：
10.1152/ajpregu.00106.2012
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Lai,Nicola
中科院分区：
文献类型：
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作者：
Spires,Jessica;Gladden,LBruce;Grassi,Bruno;Saidel,GeraldM;Lai,Nicola
根据实验研究，骨骼肌中细胞内 O2(iPo2) 与做功率 (WR) 的关系并不是唯一的。一项研究发现 iPo2 在最大 WR 的 60% 处达到稳定水平，而另一项研究发现 iPo2 在较高 WR 时线性下降，推断毛细血管通透性表面积 (PS) 和血液组织 O2 梯度分别是确定运动期间 O2 扩散变化的替代主导因素。这种关系受到多种因素的影响，包括氧气输送以及肌肉的氧化和糖酵解能力。在这项研究中，使用机械数学模型来检查这些因素，以分析收缩骨骼肌的实验数据，并预测肌肉收缩对 O2 运输、糖原分解和 iPo2 的影响。该模型描述了对流、O2 扩散和细胞代谢，包括无氧糖原分解。因此，该模型模拟了各种实验条件下 iPo2in 对肌肉收缩的反应。通过比较吸氧模拟与电刺激犬肌肉在不同氧气含量、血流量和收缩强度下的相应实验反应，对该模型进行了验证。该模型允许假设 PS、糖原分解能力和血流量的变化，并预测这些因素对犬肌肉 iPo2 收缩强度关系的独特影响。虽然PS是调节O2扩散速率的主要因素，但模型模拟表明PS和O2梯度具有重要作用，具体取决于具体条件。此外，该模型预测不同的对流和扩散模式以及代谢因素可能导致人类不同的 iPo2-WR 关系。
On the basis of experimental studies, the intracellular O2(iPo2)-work rate (WR) relationship in skeletal muscle is not unique. One study found that iPo2reached a plateau at 60% of maximal WR, while another found that iPo2decreased linearly at higher WR, inferring capillary permeability-surface area (PS) and blood-tissue O2gradient, respectively, as alternative dominant factors for determining O2diffusion changes during exercise. This relationship is affected by several factors, including O2delivery and oxidative and glycolytic capacities of the muscle. In this study, these factors are examined using a mechanistic, mathematical model to analyze experimental data from contracting skeletal muscle and predict the effects of muscle contraction on O2transport, glycogenolysis, and iPo2. The model describes convection, O2diffusion, and cellular metabolism, including anaerobic glycogenolysis. Consequently, the model simulates iPo2in response to muscle contraction under a variety of experimental conditions. The model was validated by comparison of simulations of O2uptake with corresponding experimental responses of electrically stimulated canine muscle under different O2content, blood flow, and contraction intensities. The model allows hypothetical variation ofPS, glycogenolytic capacity, and blood flow and predictions of the distinctive effects of these factors on the iPo2-contraction intensity relationship in canine muscle. AlthoughPSis the main factor regulating O2diffusion rate, model simulations indicate thatPSand O2gradient have essential roles, depending on the specific conditions. Furthermore, the model predicts that different convection and diffusion patterns and metabolic factors may be responsible for different iPo2-WR relationships in humans.