Epidemiology of HIV among female sex workers, their clients, men who have sex with men and people who inject drugs in West and Central Africa.

OBJECTIVE

The aim of this study was to evaluate the effect of micro ribonucleic acid (miR)-26a on myocardial ischemia-reperfusion (I/R) injury in rats and to explore its potential mechanism. Our findings might help to provide references for clinical prevention and treatment of myocardial I/R.

MATERIALS AND

METHODS

A total of 60 male Sprague-Dawley (SD) rats were randomly divided into three groups using a random number table, including: Control group (n=20), I/R group (n=20) and I/R + miR-26a siRNA group (n=20). I/R model was established via recanalization after ligation of left anterior descending coronary artery (LAD). The model of miR-26a knockdown was established in rats of I/R + miR-26a siRNA group via tail intravenous injection of miR-26a siRNA. Ejection fraction (EF%) and fractional shortening (FS%) of rats in each group were detected via echocardiography. The infarction area of each group was detected via 2,3,5-triphenyltetrazolium chloride (TTC) assay. Subsequently, morphological changes in myocardial cells of each group were detected via hematoxylin-eosin (H&E) staining. Myocardial apoptosis level was measured via terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. At the same time, the expression levels of pro-apoptotic proteins Bcl-2 associated X protein (Bax) and cleaved (C)-caspase3 in myocardial tissues of the three groups were determined using Western blotting. Finally, the effects of miR-26a knockdown on the expressions of glycogen synthase kinase (GSK)-3β/β-catenin signaling pathway-related proteins were detected via Western blotting and immunohistochemistry.

RESULTS

The expression of miR-26a in myocardial tissues of I/R group increased significantly when compared with that in Control group (p<0.05). Knockdown of miR-26a significantly improved cardiac insufficiency caused by I/R, which also obviously increased both EF% and FS% in rats (p<0.05). In addition, knockdown of miR-26a significantly inhibited myocardial infarction caused by I/R injury, and reduced infarction area from (43.08±2.43) to (21.54±1.82) (p<0.05). The results of H&E staining revealed that in I/R + miR-26a siRNA group, myofilaments were arranged more orderly, the degree of degradation and necrosis was significantly lower, and cellular edema was significantly alleviated when compared with I/R group. Subsequent TUNEL staining demonstrated that rats in I/R + miR-26a siRNA group showed a remarkably lower level of myocardial apoptosis than I/R group (p<0.05). Meanwhile, the protein expression levels of Bax and C-caspase3 were remarkably declined in I/R + miR-26a siRNA group (p<0.05). Furthermore, the results of Western blotting showed that miR-26a siRNA could significantly reverse the inhibition of GSK-3β/β-catenin signaling pathway induced by I/R injury (p<0.05).

CONCLUSIONS

Knockdown of miR-26a could significantly improve I/R-induced myocardial injury and promote cardiac function in rats. The possible underlying mechanism might be related to targeted regulation of miR-26a on GSK-3β/β-catenin signaling pathway. Therefore, miR-26a was expected to be a new therapeutic target for myocardial I/R injury.