Satellite cell differentiation in goat skeletal muscle single fiber culture

Satellite cells are skeletal muscle progenitor/stem cells that reside between the basal lamina and plasma membranes of skeletal muscle fibers in vivo and can give rise to both myogenic and adipogenic cells. The isolated skeletal muscle single fiber culture is an in vitro model that has the advantage of enabling the researcher to monitor the differentiation of satellite cells in a closer microenvironment found in living muscle in vivo. The aim of the present study was to establish single fiber culture of goat skeletal muscle and monitor satellite cell differentiation in this system. Fine single fibers were isolated from goat intercostal muscle by enzymatic treatment, and satellite cells on the fibers were analyzed immunocytochemically. Satellite cells on freshly isolated fibers were positive for Pax7, but negative for MyoD and myogenin, indicating that they are quiescent. As the culture period progressed, the satellite cells became positive for myogenic markers MyoD and myogenin. The satellite cells that detached from the fiber and migrated onto the culture dish were positive for both MyoD and myogenin, and some of them formed multinucleated myosin heavy chain-positive myotubes. In addition, hypercontraction of isolated fine fibers induced adipogenic differentiation of satellite cells. The present study is the first to describe establishment of a goat skeletal muscle single fiber culture that can be used as a model system for further studies on satellite cell behavior in ruminants.