In vitro myoblast motility models: investigating migration dynamics for the study of skeletal muscle repair

Skeletal muscle repair requires the migration of myoblasts (activated satellite cells) both to the injury site and then within the wound to facilitate cellular alignment in preparation for differentiation, fusion and eventual healing. Along this journey, the cells encounter a range of soluble and extracellular matrix factors which regulate their movement and ultimately determine how successful the repair process will be. Sub-optimal migration can lead to a number of scenarios, including reduced myoblast numbers entering the wound, poor alignment and insufficient differentiation to correctly repair the damage. It is therefore critical that all aspects of myoblast migration are understood, particularly in response to the changing growth and matrix factor profile prevalent following skeletal muscle injury. Since 1962, when Boyden first introduced his chemotactic chamber, numerous in vitro migration assays have been developed to mimic the wound more closely. These have increased in complexity to account for the complex micro-environment found in vivo during muscle repair and include a range of modified cell exclusion, chemotactic and three-dimensional assays. This review describes and discusses these advances and highlights the importance they have in expanding our understanding of myoblast migration dynamics.