Prolonged unloading of skeletal muscle, a common outcome of events such as spaceflight, bed rest and hindlimb unloading, can result in extensive metabolic, structural and functional changes in muscle fibres. With advancement in investigations of cellular and molecular mechanisms, understanding of disuse muscle atrophy has significantly increased. However, substantial gaps exist in our understanding of the processes dictating muscle plasticity during unloading, which prevent us from developing effective interventions to combat muscle loss. This review aims to update the status of knowledge and underlying mechanisms leading to cellular and molecular changes in skeletal muscle during unloading. We have also discussed advances in the understanding of contractile dysfunction during spaceflights and in ground-based models of muscle unloading. Additionally, we have elaborated on potential therapeutic interventions that show promising results in boosting muscle mass and strength during mechanical unloading. Finally, we have identified key gaps in our knowledge as well as possible research direction for the future.

中文翻译：

---

肌肉卸载：航天模型与地面模型之间的比较。

长时间的骨骼肌肉卸载是航天，卧床休息和后肢卸载等事件的常见结果，可导致肌肉纤维的新陈代谢，结构和功能发生广泛变化。随着细胞和分子机制研究的进展，对废用性肌肉萎缩症的了解已大大增加。但是，在我们了解决定卸载过程中肌肉可塑性的过程时，仍然存在很大的差距，这使我们无法开发出有效的干预措施来对抗肌肉损失。这项审查旨在更新知识的状态和潜在的机制，导致在卸载过程中骨骼肌细胞和分子的变化。我们还讨论了在太空飞行中对收缩功能障碍的理解以及地面肌肉卸载模型中的进展。此外，我们已经详细阐述了潜在的治疗干预措施，这些措施在机械卸载过程中显示了在增强肌肉质量和力量方面的有希望的结果。最后，我们确定了我们知识的主要差距以及未来可能的研究方向。