Muscle stem cells (or muscle satellite cells [MuSCs]) are required for postnatal growth. Yet, the detailed characterization of myogenic progression and establishment of quiescence during this process remains poorly documented. Here, we provide an overview of myogenic cells heterogeneity and dynamic from birth to adulthood using flow cytometry. We demonstrated that PAX7+ cells acquire an increasing ability to progress in the myogenic program from birth to adulthood. We then simultaneously analyzed the cycling state (KI67 expression) of the MuSCs and progenitors (PAX7+) and their progression into myogenic precursors (PAX7−MYOD+) and differentiating cells (MYOG+) in vivo. We identified two distinct peaks of myogenic differentiation between P7–P10 and P21–P28, and showed that the quiescent MuSC pool is established between 7 and 8 weeks of age. Overall our study provides a comprehensive in vivo characterization of myogenic heterogeneity and demonstrates the highly dynamic nature of skeletal muscle postnatal growth process.

出生后的生长需要肌肉干细胞（或肌肉卫星细胞[MuSCs]）。然而，在此过程中肌原性进程的详细特征和静止的建立仍然鲜有文献记载。在这里，我们提供了使用流式细胞仪从出生到成年的成肌细胞异质性和动态的概述。我们证明了PAX7 +细胞在从出生到成年的成肌程序中具有越来越强的进展能力。然后，我们同时分析了MuSCs和祖细胞（PAX7 +）的循环状态（KI67表达），以及它们在体内向成肌前体（PAX7-MYOD +）和分化细胞（MYOG +）的进展。。我们确定了P7–P10和P21–P28之间的肌源性分化的两个不同的峰值，并表明静止的MuSC库建立在7至8周龄之间。总的来说，我们的研究提供了肌异质性的全面体内表征，并证明了骨骼肌产后生长过程的高度动态性。