Department of Orthopaedic Surgery, School of Medicine, University of California San Diego, La Jolla, CA 92093, USA.
Biomedical Sciences Graduate Program, School of Medicine, University of California San Diego, La Jolla, CA 92093, USA.
Function (Oxf). 2024 Nov 20;5(6). doi: 10.1093/function/zqae035.
A growing body of data suggests that skeletal muscle contractile function and glucose metabolism vary by time-of-day, with chronobiological effects on intrinsic skeletal muscle properties being proposed as the underlying mediator. However, no studies have directly investigated intrinsic contractile function or glucose metabolism in skeletal muscle over a 24 h circadian cycle. To address this, we assessed intrinsic contractile function and endurance, as well as contraction-stimulated glucose uptake, in isolated extensor digitorum longus and soleus from mice at 4 times-of-day (zeitgeber times 1, 7, 13, 19). Significantly, though both muscles demonstrated circadian-related changes in gene expression, there were no differences between the 4 time points in intrinsic contractile function, endurance, and contraction-stimulated glucose uptake, regardless of sex. Overall, these results suggest that time-of-day variation in exercise performance and the glycemia-reducing benefits of exercise are not due to chronobiological effects on intrinsic muscle function or contraction-stimulated glucose uptake.
越来越多的数据表明，骨骼肌的收缩功能和葡萄糖代谢随时间变化而变化，内在的骨骼肌特性的生物钟效应被认为是潜在的介导因素。然而，目前还没有研究直接在 24 小时昼夜节律周期内研究骨骼肌的内在收缩功能或葡萄糖代谢。为了解决这个问题，我们评估了分离的伸趾长肌和比目鱼肌在 4 个时间点（时间点 1、7、13、19）的内在收缩功能和耐力，以及收缩刺激的葡萄糖摄取。尽管这两种肌肉的基因表达都存在昼夜节律相关的变化，但无论性别如何，内在收缩功能、耐力和收缩刺激的葡萄糖摄取在 4 个时间点之间均无差异。总的来说，这些结果表明，运动表现的时间变化和运动的降血糖益处不是由于内在肌肉功能或收缩刺激的葡萄糖摄取的生物钟效应所致。
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