EVALUATION AT PLASMID DNA FOR IN-VIVO GENE-THERAPY - FACTORS AFFECTING THE NUMBER OF TRANSFECTED FIBERS

Gene transfer by intramuscular injection of plasmid DNA has potential application in gene therapy. We examined factors affecting the number of expressing fibers, in contrast to total expression, following injec tion of plasmid DNA. Barium chloride proved effective in inducing musc le necrosis and regeneration in mice, and this increased the number of fibers expressing a reporter gene. Coinjection of ion-channel modulat ors did not increase the number of positive fibers, but increasing dos e and repeated administration of plasmid did. Importantly, the plasmid size (7-16 kb) did not affect the number of fibers expressing the tra nsgene, in both normal and regenerating muscle.