Influences of remifentanil on myocardial ischemia-reperfusion injury and the expressions of Bax and Bcl-2 in rats.

OBJECTIVE: To investigate the influences of remifentanil on myocardial ischemia-reperfusion injury in rats and the expressions of b-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax) and other apoptosis-related proteins.

MATERIALS AND METHODS: A total of 60 Sprague-Dawley (SD) rats were randomly divided into sham operation (S) group, model (M) group, low-dose remifentanil (L) group and high-dose remifentanil (H) group, with 15 rats in each group. The rat model of myocardial ischemia-reperfusion injury was established by the ligation of the left anterior descending branch (LAD). After ischemia for 30 min and reperfusion for 24 h, the cardiac function of rats in each group was measured by an ultrasonic instrument. Triphenyl tetrazolium chloride (TTC) staining was used to detect the myocardial infarction area of rats in each group. The activity of myocardial enzymes in the serum of rats in each group was detected. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining was adopted to examine the apoptosis level of rat cardiomyocytes in each group. Quantitative polymerase chain reaction (qPCR) and Western blotting were applied to detect the expression levels of apoptosis-related proteins and messenger ribonucleic acids (mRNAs) in rat cardiomyocytes in each group.

RESULTS: Compared with those in S group, left ventricular internal dimension in systole (LVIDs) and left ventricular internal dimension in diastole (LVIDd) were markedly increased (p<0.01), while left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) were notably decreased in M group (p<0.01). LVIDs and LVIDd in L group and H group were lower than those in M group (p<0.05, p<0.01), whereas LVEF and LVFS were higher than those in M group (p<0.05, p<0.01). The myocardial infarction area in M group was significantly larger than that in S group (p<0.01), and those in L group and H group were remarkably smaller than that in M group (p<0.05, p<0.01). The activities of aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and creatine kinase-muscle/brain (CK-MB) in the serum of rats in M group were evidently higher than those in S group (p<0.01), and compared with those in M group, those in L group and H group were significantly decreased (p<0.05, p<0.01). The apoptosis level of myocardial cells in M group was significantly higher than that in S group (p<0.01), while those in L group and H group were markedly lower than that in M group (p<0.05, p<0.01). Compared with those in S group, the expression levels of cleaved caspase-3 and its mRNAs in myocardial cells in M group were remarkably increased (p<0.01), while those of Bcl-2/Bax and it mRNAs were significantly decreased (p<0.01). The expression levels of cleaved caspase-3 and its mRNAs in myocardial cells in L group and H group were significantly lower than those in M group (p<0.05, p<0.01), but those of Bcl-2/Bax and its mRNAs were significantly higher than those in M group (p<0.05, p<0.01).

CONCLUSIONS: Remifentanil can effectively reduce myocardial cell injury caused by myocardial ischemia-reperfusion in rats, improve cardiac function, reduce the myocardial infarction area, decrease cleaved caspase-3 in myocardial cells, and increase Bcl-2/Bax.