AIMTo determine if the diagnostic ultrasound and self-made microbubbles could be used to increase gene transfection and expression in cardiac myocytes by means of the ultrasound-mediated microbubbles destruction.

METHODSThe perfluoropropane-exposed sonicated dextrose albumin(PESDA) microbubbles were made and mixed with indicated volume reporter gene encoding beta-galactosidase prior to gene transfection. Gene transfection into the cultured cardiac myocytes was performed by exposure to the various intense diagnostic ultrasound (1.3 MHz) in the presence of the gene-attached microbubbles. The calcium phosphate precipitation gene transfection was carried out alone or in combination with ultrasound-mediated destruction microbubbles. The cells were harvested 48 h after transfection and beta-galactosidase expression was detected by in situ staining and quantitive assay.

RESULTSCardiac myocytes exposed to ultrasound with PESDA induced significantly increase in gene expression (60-fold compared with naked plasmids transfection, P < 0.01). Moreover, it was found that the reporter gene expression not only related with ultrasound intension but also with the microbubbles concentration. In combination with calcium phosphate precipitation gene transfection, ultrasound-mediated destruction microbubbles resulted in more intense gene expression even 6 hours after calcium phosphate precipitation gene transfection.

CONCLUSIONThe ultrasonic destruction of gene-loaded microbubble is a highly effective gene transfer method, and it not only acts on the gene entry into cells, but also on the intracellular exogenous DNA expression.