ABSTRACT
In vivo electroporation has emerged as a leading technology for developing nonviral gene therapies, and the various technical parameters governing electroporation efficiency have been optimized by both theoretical and experimental analysis. However, most electroporation parameters focused on the electric conditions and the preferred vehicle for plasmid DNA injections has been normal saline. We hypothesized that salts in vehicle for plasmid DNA must affect the efficiency of DNA transfer because cations would alter ionic atmosphere, ionic strength, and conductivity of their medium. Here, we show that half saline (71 mM) is an optimal vehicle for in vivo electroporation of naked DNA in skeletal muscle. With various salt concentrations, two reporter genes, luciferase and beta-galactosidase were injected intramuscularly under our optimal electric condition (125 V/cm, 4 pulses x 2 times, 50 ms, 1 Hz). Exact salt concentrations of DNA vehicle were measured by the inductively coupled plasma-atomic emission spectrometer (ICP-AES) and the conductivity change in the tissue induced by the salt in the medium was measured by Low-Frequency (LF) Impedance Analyzer. Luciferase expression in-creased as cation concentration of vehicle dec-reased and this result can be visualized by X-Gal staining. However, at lower salt concentration, transfection efficiency was diminished because the hypoosmotic stress and electrical injury by low conductivity induced myofiber damage. At optimal salt concentration (71 mM), we observed a 3-fold average increase in luciferase expression in comparison with the normal saline condition (p < 0.01). These results provide a valuable experimental parameter for in vivo gene therapy mediated by electroporation.
Subject(s)
Animals , Female , Mice , Comparative Study , DNA/administration & dosage , Drug Delivery Systems , Electric Conductivity , Electroporation/methods , Escherichia coli/genetics , Genetic Therapy/methods , Gene Transfer Techniques , Genes, Reporter , Injections, Intramuscular , Luciferases/metabolism , Mice, Inbred BALB C , Muscle, Skeletal/drug effects , Osmolar Concentration , Plasmids/genetics , Sodium Chloride/pharmacology , Transfection , Pharmaceutical Vehicles/administration & dosage , beta-Galactosidase/metabolismABSTRACT
In vivo electroporation has emerged as a leading technology for developing nonviral gene therapies, and the various technical parameters governing electroporation efficiency have been optimized by both theoretical and experimental analysis. However, most electroporation parameters focused on the electric conditions and the preferred vehicle for plasmid DNA injections has been normal saline. We hypothesized that salts in vehicle for plasmid DNA must affect the efficiency of DNA transfer because cations would alter ionic atmosphere, ionic strength, and conductivity of their medium. Here, we show that half saline (71 mM) is an optimal vehicle for in vivo electroporation of naked DNA in skeletal muscle. With various salt concentrations, two reporter genes, luciferase and beta-galactosidase were injected intramuscularly under our optimal electric condition (125 V/cm, 4 pulses x 2 times, 50 ms, 1 Hz). Exact salt concentrations of DNA vehicle were measured by the inductively coupled plasma-atomic emission spectrometer (ICP-AES) and the conductivity change in the tissue induced by the salt in the medium was measured by Low-Frequency (LF) Impedance Analyzer. Luciferase expression in-creased as cation concentration of vehicle dec-reased and this result can be visualized by X-Gal staining. However, at lower salt concentration, transfection efficiency was diminished because the hypoosmotic stress and electrical injury by low conductivity induced myofiber damage. At optimal salt concentration (71 mM), we observed a 3-fold average increase in luciferase expression in comparison with the normal saline condition (p < 0.01). These results provide a valuable experimental parameter for in vivo gene therapy mediated by electroporation.
Subject(s)
Animals , Female , Mice , Comparative Study , DNA/administration & dosage , Drug Delivery Systems , Electric Conductivity , Electroporation/methods , Escherichia coli/genetics , Genetic Therapy/methods , Gene Transfer Techniques , Genes, Reporter , Injections, Intramuscular , Luciferases/metabolism , Mice, Inbred BALB C , Muscle, Skeletal/drug effects , Osmolar Concentration , Plasmids/genetics , Sodium Chloride/pharmacology , Transfection , Pharmaceutical Vehicles/administration & dosage , beta-Galactosidase/metabolismABSTRACT
BACKGROUND: Recently, we have reported that biodegradable poly [-(4-aminobutyl)-L-glycolic acid] (PAGA) can condense and protect plasmid DNA from DNase I. In this study, we investigated whether the systemic administration of pCAGGS mouse IL-10 (mIL-10) expression plasmid complexed with PAGA can reduce the development of insulitis in non-obese diabetic (NOD) mice. METHODS: PAGA/mIL-10 plasmid complexes were stable for more than 60 minutes, but the naked DNA was destroyed within 10 minutes by DNase I. The PAGA/DNA complexes were injected into the tail vein of 3 week-old NOD mice. RESULTS: Serum mIL-10 level peaked at 5 days after injection, could be detected for more than 7 weeks. The prevalence of severe insulitis at 12 week-old NOD mice was markedly reduced by the intravenous injection of PAGA/DNA complex (15.7%) compared to that of naked DNA injection (34.5%) and non-treated controls (90.9%). In conclusion, systemic administration of pCAGGS mIL-10 plasmid/PAGA complexes can reduce the severity of insulitis in NOD mice. CONCLUSION: The study presents the PAGA/DNA complex has the potential for the application of the prevention of autoimmune diabetes mellitus.