In Vivo Electroporation of Plasmid DNA into the Skeletal Muscle of Dystrophic Mouse Models

Gene transfer into living, adult skeletal muscle in experimental animals is a powerful tool for investigating the fundamental molecular mechanisms of neuromuscular disease progression. This methodology has been leveraged in the development of potential therapeutics for Duchenne muscular dystrophy (DMD), limb girdle muscular dystrophies (LGMD), and other skeletal muscle maladies. There are several modalities for gene transfer into skeletal muscle, including the use of viral vectors, nucleic acid encapsulation, and the development of transgenic mouse models. However, there are distinct advantages to the use of electroporation to deliver plasmid DNA in the preclinical setting. Electroporation applies an electric current to biological tissues that produce small, transient pores in the plasma membrane of cells. At high concentrations, plasmid DNA or other nucleic acid constructs can enter through these membrane disruptions and become enclosed within the cell after membrane resealing. This allows for rapid modification of gene expression or gene editing in target cells. Thus, electroporation represents a tractable and efficient method for tissue-specific gene delivery into the muscles of many mouse models, including those for DMD and other muscular dystrophies. In the specific approach detailed here, transdermal electric pulses applied to the hindlimb permeabilize the sarcolemmal membrane in vivo, allowing for plasmid DNA transfection of adult myofibers in dystrophic mice. We delineate the methodology for in vivo electroporation of the flexor digitorum brevis muscle for efficient plasmid gene transfer in dystrophic and wild-type mouse models.