LAUSR

OBJECTIVE To elucidate the protective role of resveratrol (RSV) in myocardial apoptosis induced by ischemia-reperfusion injury in rats with acute myocardial infarction (AMI), and to explore its underlying mechanism. MATERIALS AND METHODS The AMI rat model was successfully established by ligation of the left anterior descending coronary artery. Rat cardiomyocytes were isolated and cultured. Cells were divided into four groups, including: control group (no specific treatment), AMI group (acute ischemia-reperfusion treatment), AMI+RSV group (RSV pretreatment for 24 h before acute ischemia-reperfusion) and AMI+ RSV+LY group (RSV pretreatment combined with 40 μmol/L phosphatidylinositide 3-kinases (PI3K) pathway inhibitor LY294002 for 24 h before acute ischemia-reperfusion). Morphology of apoptotic cardiomyocytes in each group was observed by Hoechst staining. The proliferation, apoptosis and cell cycle progression of cardiomyocytes were determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay, terminal dexynucleotidyl transferase(TdT)-mediated dUTP nick end labeling (TUNEL) assay and flow cytometry, respectively. Finally, the protein levels of genes relative to PI3K/Akt/eNOS pathway were detected by Western blot. RESULTS Hoechst staining showed a large number of necrotic cells, cell retraction, enhanced refractive index and enlarged cell gap in AMI group. A small number of necrotic cells were found in AMI+RSV group, which was significantly fewer than that of AMI group. Meanwhile, remaining cells presented normal morphology. However, a great number of necrotic cells were observed in AMI+RSV+LY group, which was obviously more than that of AMI+RSV group. Compared with control group, cells in AMI group showed significantly decreased proliferative rate, increased early phase, late phase and total one of apoptosis. In AMI group, the ratio of G0/G1 phase was remarkably increased, whereas those of S and G2/M phases were decreased. Moreover, the expression levels of phosphorylated Akt (p-Akt) and phosphorylated e-NOS (p-eNOS) were significantly downregulated in AMI group. In AMI+RSV group, cell apoptosis, cell cycle progression and levels of p-Akt and p-eNOS showed the opposite trends as those of AMI group. However, LY294002 pretreatment reversed the protective role of RSV in cellular behaviors of cardiomyocytes. CONCLUSIONS RSV protects cardiomyocyte apoptosis from ischemia-reperfusion injury through regulating phosphorylation levels of proteins relative to PI3K/Akt/e-NOS pathway.