ABSTRACT
Objective:To investigate the myocardial protective effect of extracorporeal cardiac shock wave therapy (CSWT) combined with sulfur hexafluoride microbubble post-conditioning on myocardial ischemia-reperfusion injury (MI/RI) in rats, and to provide theoretical support for clinical treatment of MI/RI.Methods:A total of 32 male SD rats were randomly divided into 4 groups: sham operation group (Sham group), MI/RI group (IR group), CSWT group (IR+ SW group), and CSWT combined with sulfur hexafluoride microbubble treatment group (IR+ SW+ MB group), with 8 rats in each group. Therapeutic intervention was performed in IR+ SW group and IR+ SW+ MB group on the 1st, 3rd and 5th day after modeling. The left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD), left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) of the rats were measured by echocardiography before and after treatment. On the 7th day, myocardial fibrosis was assessed by Masson staining, and cardiomyocyte apoptosis was observed by TUNEL staining. The myocardial apoptotic proteins Bcl-2, BAX, Cleaved-Caspase-3 and Cleaved-Caspase-9 in the infarct boundary area were detected by Western blot. The differences of the above indexes among different groups were compared.Results:①There was no significant change in heart rhythm and heart rate among the groups before and after treatment, and there was no significant difference in heart rate ( P>0.05). ②The echocardiographic results after treatment showed that, compared with IR group, LVEDD and LVESD in IR+ SW group and IR+ SW+ MB group decreased in turn, while LVEF and LVFS increased in turn with significant differences between each two groups (all P<0.05). ③Compared with IR group, the degrees of myocardial fibrosis and apoptosis in IR+ SW group and IR+ SW+ MB group were alleviated in turn, and the relief in IR+ SW+ MB group was the most obvious. Quantitative analysis showed that compared with IR group, the proportions of cardiomyocyte apoptosis in IR+ SW group and IR+ SW+ MB group decreased in turn, and there were significant differences between each two groups (all P<0.05). ④The results of Western blot detection showed that compared with IR group, the levels of Bcl-2 in IR+ SW group and IR+ SW+ MB group increased in turn, while the levels of BAX and the activation level of Caspase-3 and Caspase-9 protein decreased in turn. These differences were all statistically significant between each two groups (all P<0.05) except for the activation level of Caspase-3 protein between IR+ SW group and IR+ SW+ MB group ( P>0.05). Conclusions:CSWT combined with sulfur hexafluoride microbubble therapy can improve left ventricular remodeling and left ventricular systolic function by inhibiting cardiomyocyte apoptosis.