Optical in vivo imaging of electrically mediated delivery of siRNA into muscle for gene function analysis.

Short interfering RNAs (siRNAs) represent new potential therapeutic tools owing to their capacity to induce strong, sequence-specific gene silencing in cells. However, this development requires new, safe, and efficient in vivo siRNA delivery methods. In this study, we reported that gene silencing was efficiently obtained in vivo in an adult mammal (mouse) with chemically synthesized siRNA after its electrical delivery in muscles. The associated gene silencing was followed on the same animal and lasted more than 11 days. Gene silencing was obtained in muscles not only on young adult mice but also on much older animals. No tissue damage was detected under our electrical conditions. Therefore, this method should provide an efficient approach for gene function analysis by a localized delivery of siRNAs.