Muscle transfection by electroporation with high-voltage and short-pulse currents provides high-level and long-lasting gene expression

Gene transfer into muscle by electroporation with low-voltage and long-puls e (LV/LP, 100 V/50 msec) currents was shown to be more efficient than simpl e intramuscular DNA injection, Nevertheless, transgene expression declined from day 7 and only reached 10% of the maximum 3 weeks after electroporatio n, We have optimized electroporation conditions including voltage, pulse nu mber, and the amount of injected luciferase-encoding plasmid DNA in the tib ialis anterior muscle. Using high-voltage and short-pulse (HV/SP, 900 V/100 mu sec) currents, we observed an average 500-fold increase in luciferase e xpression, in comparison with non-electroporated muscle. Moreover, sustaine d and long-lasting gene expression was observed for at least 6 months. When we compared HV/SP currents with LV/LP currents, luciferase expression was similar 24 hr after electroporation. One month later, whereas luciferase ex pression was stable in muscle electroporated with HV/SP currents, it decrea sed 600-fold in muscle electroporated with LV/LP currents. In conclusion, e lectroporation with high-voltage and short-pulse currents provides high-lev el and long-lasting gene expression in muscle.