Effects of P85 and microbubbles on the efficiency of ultrasound-induced gene transduction in skeletal muscle of mice in vivo

Abstract

Objective To explore the effects of P85,microbubbles and ultrasound on plasmid DNA skeletal muscle gene transduction of mice in vivo. Methods Plasmid encoding green fluorescent protein (GFP) ,which conjugated with 0.05% P85 and/or microbubbles, 10% Optison,was injected into the tibialis anterior(TA) muscle of mice with or without ultrasound irradiation (1 MHz, 1 W/cm2 2 min,20% duty cycle). Mice were killed 1 week after injection. The TA muscles were removed and snap-frozen immediately in isopentane cooled by liquid nitrogen and sections 7 μm thick were cut at intervals. One set of sections mounted with DAPI were used to assess the transfection efficiency by counting the number of GFP-positive fibers under fluorescence microscopy,and the other set of sections were stained with haematoxylin and eosin to assess the tissue damage area. Results The P85 and Optison significantly enhanced the plasmid DNA skeletal muscle gene delivery in vivo separately (P 0.05).The gene delivery efficiency induced by P85 was higher than that by Optison no matter with or without ultrasound irradiation(P<0.01). When the P85 conjugated with Optison, they could further significantly enhance gene delivery efficiency with ultrasound exposure (P<0.01). Meanwhile, ultrasound exposure could increase the muscle damage areas in the groups with microbubbles (P<0.01). Conclusions The P85,microbubbles and ultrasound exposure display synergistic effect to enhance plasmid DNA transduction in skeletal muscle of mice in vivo. Key words: Ultrasonography; Microbubbles; Muscle, skeletal; Transfection; Pluronic block copolymer