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Abstract：
Composed of a diverse variety of cells, the skeletal muscle is one of the body\'s tissues with the remarkable ability to regenerate after injury. One of the key players in the regeneration process is the muscle satellite cell (MuSC), a stem cell population for skeletal muscle, as it is the source of new myofibers. Maintaining MuSC quiescence during homeostasis involves complex interactions between MuSCs and other cells in their corresponding niche in adult skeletal muscle. After the injury, MuSCs are activated to enter the cell cycle for cell proliferation and differentiate into myotubes, followed by mature myofibers to regenerate muscle. Despite decades of research, the exact mechanisms underlying MuSC maintenance and activation remain elusive. Traditional methods of analyzing MuSCs, including cell cultures, animal models, and gene expression analyses, provide some insight into MuSC biology but lack the ability to replicate the 3-dimensional (3-D) in vivo muscle environment and capture dynamic processes comprehensively. Recent advancements in imaging technology, including confocal, intra-vital, and multi-photon microscopies, provide promising avenues for dynamic MuSC morphology and behavior to be observed and characterized. This chapter aims to review 3-D and live-imaging methods that have contributed to uncovering insights into MuSC behavior, morphology changes, interactions within the muscle niche, and internal signaling pathways during the quiescence to activation (Q-A) transition. Integrating advanced imaging modalities and computational tools provides a new avenue for studying complex biological processes in skeletal muscle regeneration and muscle degenerative diseases such as sarcopenia and Duchenne muscular dystrophy (DMD).
摘要：
由各种各样的细胞组成，骨骼肌是人体损伤后具有显著再生能力的组织之一。再生过程中的关键参与者之一是肌肉卫星细胞（MuSC），骨骼肌干细胞群，因为它是新肌纤维的来源。在稳态期间维持MuSC静止涉及MuSC与成年骨骼肌中相应小生境中的其他细胞之间的复杂相互作用。受伤后,MuSCs被激活进入细胞周期进行细胞增殖并分化为肌管,然后是成熟的肌纤维再生肌肉。尽管经过几十年的研究,MuSC维持和激活的确切机制仍然难以捉摸。分析MuSCs的传统方法，包括细胞培养,动物模型,和基因表达分析，提供对MuSC生物学的一些见解，但缺乏复制3维（3-D）体内肌肉环境和全面捕获动态过程的能力。成像技术的最新进展，包括共焦,活体内，和多光子显微镜，为观察和表征动态MuSC形态和行为提供了有希望的途径。本章旨在回顾3-D和实时成像方法，这些方法有助于发现对MuSC行为的见解，形态变化,肌肉小生境内的相互作用，和在静止到激活(Q-A)过渡期间的内部信号通路。整合先进的成像模式和计算工具为研究骨骼肌再生和肌肉退行性疾病（例如肌肉减少症和杜氏肌营养不良症（DMD））中的复杂生物学过程提供了新的途径。
