Isolation, in-vitro expansion, and characterization of human muscle satellite cells from the rectus abdominis muscle

Introduction: Satellite cells are a resident population of stem cells beneath the basal lamina of mature skeletal muscle fibers. Their capacity to regenerate muscle makes them a potentially ideal source for human cell therapy with respect to muscle-related diseases such as urinary and fecal incontinence, and others. In this study, we describe a protocol to isolate, expand in-vitro, and characterize human muscle satellite cells from the rectus abdominis muscle. Materials and Methods: Muscle biopsies from human donors were harvested, digested using collagenase type II, and then plated on extracellular matrix-coated plates. Results: Immunocytochemistry revealed that satellite cells on day 8 were 70–80% Pax7 positive; in contrast, cells expanded until day 12 showed 50–75% positivity for Pax7. The real-time polymerase chain reaction for day 8 culture indicated four-fold increase in Pax3 and Pax7 gene expression, four-fold increase in MyoD gene expression, and five-fold increase in Myf5 gene expression. Conclusion: These findings suggest that satellite cells can be cultured until day 8 for translational purposes. The protocol described here is modest, operational, and reproducible and involves only basic cell culture equipment.