Noninvasive Tracking of Quiescent and Activated Muscle Stem Cell (MuSC) Engraftment Dynamics In Vivo

: Muscle stem cells play a central role in muscle regeneration. Most studies in the field of muscle regeneration focus on the unraveling of muscle stem cell biology to devise strategies for treating failing muscles as seen in aging and muscle-related diseases. However, the common method used in assessing stem cell function in vivo is laborious, as it involves time-consuming immunohistological analyses by microscopy on serial cryo-sections of the muscle post stem cell transplantation. Here we describe an alternative method, which adapts the bioluminescence imaging (BLI) technique to allow noninvasive tracking of engrafted stem-cell function in vivo in real-time. This assay system enables longitudinal studies in the same mice over time and reveals parameters, not feasible by traditional analysis, such as the magnitude and dynamics of engrafted muscle stem cell expansion in vivo in response to a particular drug treatment or muscle injury.