Ultrasound/microbubble enhances foreign gene expression in ECV304 cells and murine myocardium

Although viral vectors are efficient systems to transfer foreign genes into cells or target tissues, safety issues remain in relation to human gene therapy. Microbubbles currently used as ultrasound contrast agents have been applied in transfection of genes. This study was designed to test the transfection efficiency and the expression of exogenous gene mediated by ultrasound irradiation enhanced air filled albumin microbubbles in ECV304 cell line in vitro and the heart of the mouse in vivo. Air filled microbubbles (2.0-4.0 microm in diameter) were created by sonicating the mixture of human albumin, glucose, mannitol and special additive that was designed for stabilization. Plasmid DNA loading the reporter genes was gently mixed with microbubbles. The mixture of plasmid DNA and microbubbles was administrated to cultured ECV304 cells and BALB/c mice (tail vein injection) under different ultrasound/microbubble conditions, and then the transfection and expression efficiency were examined. The results both in vivo and in vitro demonstrated that microbubble with ultrasound irradiation could significantly elevate the exogenous gene expression as compared with microbubble or ultrasound only. Overall, the present study showed that the ultrasound-target microbubble destruction method enhanced the exogenous gene expression in vivo and in vitro, and provided a gene therapy way not only efficient but also easy to be manipulated and carried out in clinical.