Skeletal Muscle Regeneration in the Mouse

Abstract

Adult skeletal muscle is maintained and repaired by resident stem cells called satellite cells, located between the plasmalemma of a muscle fi ber, and the surrounding basal lamina. When needed, satellite cells are activated to form proliferative myoblasts, that then differentiate and fuse to existing muscle fi bers, or fuse together to form replacement myofi bers. In parallel, a proportion of satellite cells self-renew, to maintain the stem cell pool. To date, Pax7 is the marker of choice for identifying quiescent satellite cells. Co-immunostaining of skeletal muscle with Pax7 and laminin allows both identifi cation of satellite cells, and the myofi ber that they are associated with. Furthermore, satellite cells can be followed through the early stages of the myogenic program by co-immunostaining with myogenic regulatory factors such as MyoD. To test genetically modifi ed mice for satellite cell expression, co-immunostaining can be performed for Pax7 and reporter genes such as eGFP. Here, we describe a method for identifi cation of satellite cells in skeletal muscle sections, including muscle isolation, cryosectioning and co-immunostaining for Pax7 and laminin.