G-T Wang1, H Li, Z-Q Yu, X-N He. 1. Daqing Campus of Harbin Medical University, Daqing, China. iceboy8899@163.com.
Abstract
OBJECTIVE: To investigate the effects of ranolazine on the cardiac function and myocardial apoptosis in rats with heart failure and its possible mechanisms. MATERIALS AND METHODS: Thirty Wistar rats were randomly divided into sham operation (negative control; NC), chronic heart failure (CHF), and ranolazine groups. Suprarenal abdominal aortic coarctation was used to induce CHF in rats. Five weeks later, rats in the ranolazine group received ranolazine (50 mg/kg) daily, whereas those in the CHF group received normal saline. After 4 weeks, changes in hemodynamic parameters, cardiac structure and pathology, myocardial apoptosis, and protein expression were assessed. RESULTS: The left ventricular end-diastolic pressure (LVEDP) significantly increased in the CHF group; whereas the maximal rate of left ventricular pressure rise and fall (±dp/dtmax) decreased, compared to those in the NC group. Ranolazine significantly reduced LVEDP and increased ±dp/dtmax (p<0.01), compared to those in the CHF group. Severe impairment of cardiomyocytes was observed in the CHF group with evident inflammation; however, ranolazine reversed these deficits. Rats in the CHF group exhibited an increase in TUNEL-positive cells, which was inhibited by ranolazine, where the apoptotic index significantly decreased in ranolazine-treated rats (p<0.01). Also, ranolazine downregulated caspase-9 expression and upregulated pAKT and Bcl-2 expression in rat cardiomyocytes. Moreover, ranolazine significantly inhibited myocardial apoptosis and caspase-9 expression, promoted AKT phosphorylation, and upregulated pAKT and Bcl-2 expression in vitro, compared to those in the control group (p<0.001). LY294002 inhibited ranolazine-induced suppression of myocardial apoptosis (p<0.001). CONCLUSIONS: Ranolazine improved cardiac function and inhibited myocardial apoptosis in rats with CHF, which could be attributed to the regulation of AKT phosphorylation.
OBJECTIVE: To investigate the effects of ranolazine on the cardiac function and myocardial apoptosis in rats with heart failure and its possible mechanisms. MATERIALS AND METHODS: Thirty Wistar rats were randomly divided into sham operation (negative control; NC), chronic heart failure (CHF), and ranolazine groups. Suprarenal abdominal aortic coarctation was used to induce CHF in rats. Five weeks later, rats in the ranolazine group received ranolazine (50 mg/kg) daily, whereas those in the CHF group received normal saline. After 4 weeks, changes in hemodynamic parameters, cardiac structure and pathology, myocardial apoptosis, and protein expression were assessed. RESULTS: The left ventricular end-diastolic pressure (LVEDP) significantly increased in the CHF group; whereas the maximal rate of left ventricular pressure rise and fall (±dp/dtmax) decreased, compared to those in the NC group. Ranolazine significantly reduced LVEDP and increased ±dp/dtmax (p<0.01), compared to those in the CHF group. Severe impairment of cardiomyocytes was observed in the CHF group with evident inflammation; however, ranolazine reversed these deficits. Rats in the CHF group exhibited an increase in TUNEL-positive cells, which was inhibited by ranolazine, where the apoptotic index significantly decreased in ranolazine-treated rats (p<0.01). Also, ranolazine downregulated caspase-9 expression and upregulated pAKT and Bcl-2 expression in rat cardiomyocytes. Moreover, ranolazine significantly inhibited myocardial apoptosis and caspase-9 expression, promoted AKT phosphorylation, and upregulated pAKT and Bcl-2 expression in vitro, compared to those in the control group (p<0.001). LY294002 inhibited ranolazine-induced suppression of myocardial apoptosis (p<0.001). CONCLUSIONS:Ranolazine improved cardiac function and inhibited myocardial apoptosis in rats with CHF, which could be attributed to the regulation of AKT phosphorylation.