In vivo DNA electrotransfer into muscle.

Naked plasmid DNA injected into skeletal muscle is taken up by muscle cells and the genes in the plasmid are expressed. Among the non-viral techniques for gene transfer in vivo, this method is especially simple, inexpensive, and safe. However, the relatively low expression levels attained by this method have limited its applications for uses other than as a DNA vaccine. We and other groups investigated the applicability of in vivo electroporation for gene transfer into muscle, using plasmid DNA vector. The results demonstrated that gene transfer into muscle by in vivo electroporation is far more efficient than simple intramuscular DNA injection and provides a potential approach to systemically delivering cytokines, growth factors, and other serum proteins for basic research and human gene therapy.