In vitro and in vivo studies have demonstrated that inhibition of
phospholamban (PLB) expression in myocardium can restore left ventricular systolic function in failing heart. Ultrasound mediated
microbubble destruction provides a new option for noninvasive gene transfer in heart. In this study, we transferred pAAV-antisense
phospholamban (pAAV-asPLB) to the hearts of
myocardial infarction (MI) mice, using ultrasound mediated
microbubble destruction. Then we estimated the
protein levels of PLB, Ser16-PLB and cardiac
sarcoplasmic reticulum Ca(2+) ATPase (SERCA). The left ventricular ejection fraction (LVEF), fraction shortening (FS) and SERCA activity were measured as well. MI mice were generated by ligating the left anterior descending coronary artery.
Microbubbles were prepared by sonicated
perfluorocarbon gas with
dextrose and
albumin. A mixture of pAAV-asPLB plasmid and
microbubble was injected via tail vein while the heart was simultaneously exposed to ultrasound via transthoracic insonation. Three weeks later, LVEF (48.2+/-5.18% vs 39.1+/-5.38%, p<0.05), FS (19.6+/-2.59% vs 16.0+/-2.29%, p<0.05), SERCA activity (3.00+/-0.29 vs 2.12+/-0.30, p<0.05) and Ser16-PLB
protein level (0.8+/-0.25 vs 0.46+/-0.18, p<0.05) were increased while PLB
protein level (1.45+/-0.38 vs 2.05+/-0.31, p<0.05) was decreased compared with the MI mice with saline injection. The above parameters in MI mice with only pAAV-asPLB plasmid injection or pAAV-asPLB plasmid combined with ultrasound alone were not significantly improved. pAAV-LacZ was used as a reporter gene to determine the efficiency and localization of transfection. The expression of
beta-galactosidase was not found in liver, lung and brain, but found only in tubular epithelial cells of kidney and found in heart. These results confirm that asPLB gene transfection can be achieved by ultrasound mediated
microbubble destruction with organ specificity. The effective transfection can partly restore heart function in MI mice.