Effects of modified acidic fibroblast growth factor mediated by nanoliposomes combined with ultrasound-targeted microbubble destruction on left ventricular systolic function in diabetic rats

Objective To investigate the effects of modified acidic fibroblast growth factor (MaFGF) mediated by nanoliposomes combined with ultrasound-targeted microbubble destruction (UTMD) on left ventricular systolic function in early diabetes mellitus(DM) rats. Methods The nanoliposomes containing MaFGF(MaFGF-nlip) were prepared by reverse phase evaporation method. Among 60 male Sprague Dawley (SD) rats, 50 rats were randomly selected and were induced to be DM models by streptozotocin(STZ) through intraperitoneal injecting, the other 10 rats as control group. Then DM rats were randomly divided into 4 groups: DM model group, MaFGF solution group, MaFGF-nlip group and MaFGF-nlip+ UTMD group. After the successful induction of DM model, the intervention was performed twice a week.After 12 weeks of intervention, all rats underwent conventional echocardiography and velocity vector imaging (VVI). Left ventricular ejection fraction (LVEF) and left ventricular fraction shortening(LVFS) were measured by conventional echocardiography. The mean peak systolic radial velocity (Vs), radial strain (Sr) and radial strain rate (SRr) of six walls at the papillary muscle level were measured in left ventricular short-axis view by VVI. At last, myocardial tissue of all rats were stained with Sirius red to evaluate myocardial interstitial fibrosis. The level of myocardial apoptosis was evaluated by TUNEL staining, and the changes of myocardial ultrastructure were observed by transmission electron microscopy. Results The prepared MaFGF-nlip were more rounded, evenly dispersed, and of good stability and high encapsulation efficiency. Twelve weeks later after intervention, LVEF, LVFS, Vs, Sr and SRr in the DM model group were significantly lower than those in the control group (all P<0.05). LVEF, LVFS, Vs, Sr and SRr in the MaFGF-nlip+ UTMD group were significantly higher than those of the DM model group and other intervention groups (all P<0.05). The results of Sirius red staining and Tunel staining showed that CVF and AI in the DM model group were significantly higher than those in the control group (all P<0.05). For MaFGF-nlip+ UTMD group, CVF and AI were significantly decreased compared with the DM model group and other intervention groups(all P<0.05). According to the results of transmission electron microscopy, compared with the DM model group, the improvement of myocardial ultrastructure was the most obvious in the MaFGF-nlip+ UTMD group. Conclusions MaFGF delivered by using nanoliposomes combined with UTMD can improve the left ventricular systolic function in diabetic rats by inhibiting the myocardium cardiac fibrosis and reducing the cardiomyocyte apoptosis. Key words: Ultrasound-targeted microbubble destruction; Diabetic cardiomyopathy; Ventricular function, left; Nanoliposomes; Modified acidic fibroblast growth factor