Effects of ultrasound-targeted microbubble-mediated MicroRNA-21 on cardiomyocyte apoptosis after coronary microembolization in swine / 中华急诊医学杂志

ABSTRACT

Objective To investigate the effects of ultrasound-targeted microbubble destructionmediated MicroRNA-21 on cardiomyocyte apoptosis after coronary microembolization (CME) in swine.Methods Twenty Bama miniature swine were randomLy (random number) divided into sham-operated,CME,CME plus gene transfection and CME plus ultrasound mediated gene transfection groups (n =5 per group).The CME model was established by microcatheter-mediated injection of microspheres into the left anterior descending artery.The sham-operated group were made by injection of saline instead.The CME plus ultrasound mediated gene transfection group was made by injection of plasmid-microbubble mixture through the marginal ear vein 4 days before CME established.Meanwhile,ultrasound treatment was given to the myocardium through chest wall.The CME plus gene transfection group was made by injection of plasmidmicrobubble mixture through the marginal ear vein 4 days before CME established without exposure to ultrasound.Left ventricular ejection fraction (LVEF) was examined by cardiac ultrasound.Tissue biopsy was stained with hematoxylin-eosin (HE) and hematoxylin basic fuchsin picric acid (HBFP) to measure the size of infarction area.Green fluorescent protein (GFP)-labeled gene expression was evaluated by fluorescent microscopy in frozen sections.Cardiomyocyte apoptosis was detected with terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end-labeling (TUNEL staining).The expression of PTEN mRNA was measured by fluorescent quantitative PCR.The levels of PTEN protein and Caspase-3 protein was measured by western blot.Results ①Compared to CME plus gene transfection group,the CME plus ultrasound mediated gene group had over eightfold expression of exogenous genes in myocardium (P ＜ 0.05) measured by using optical density of green fluorescence protein;② Compared with shamoperated group [(67.87 ±2.36)％],the LVEF of CME group [(50.94 ±3.52)％] and CME plus gene transfection group [(52.47 ±3.71)％] were markedly decreased (P ＜ 0.05).Compared with CME group,the CME plus ultrasound mediated gene transfection group [(64.79 ± 2.95)％] improved CME-induced cardiac dysfunction as evidenced by increased LVEF (P ＜ 0.05);③Compared with sham-operated group,the expression of PTEN mRNA and levels of PTEN protein and Caspase-3 protein in the CME group increased significantly (P ＜ 0.05).Compared with CME group,the levels of PTEN protein and Caspase-3 protein and the expression of PTEN mRNA in CME plus ultrasound mediated gene transfection group was dramatically decreased (P ＜ 0.05).Conclusions Ultrasound microbubble-mediated MicroRNA-21 transfection effectively improved CME-induced cardiac dysfunction by down-regulating the expression of targeted gene PTEN in myocardial cells,mainly reducing the post-CME myocardial cell apoptosis.