Effect of Calcium Channel Blocker on Primary Rat Cardiomyoblasts and Cardiac Rate in Vitro

PURPOSE: This work was intended to establish experimental conditions for monitoring the effect of ischemic/reperfusion injury on the beating capability of, and apoptotic damage to, primary rat cardiomyoblasts, and to investigate the cardioprotective effect of calcium channel blocker on primary rat cardiomyoblasts with ischemic/reperfusion injury including reactive oxygen species damage. METHODS: To generate ischemic/reperfusion injury, primary rat cardiomyoblasts were treated with hydrogen peroxide (H2O2). Injured cardiomyoblasts were pretreated with the calcium channel blocker nicardipine. RESULTS: Treatment with H2O2 significantly decreased the cardiac rate of primary rat cardiomyoblasts in time- and dose-dependent manners. Interestingly, the cardiac rate of primary rat cardiomyoblasts abruptly dropped prior to the decrease in cell viability. H2O2 also induced a decrease in the expression of heme oxygenase-1 (HO-1) protein in P2 primary rat cardiomyoblasts in a time-dependent manner. Moreover, treatment with H2O2 resulted in an increase of DNA fragmentation, indicating that H2O2 induced the apoptotic death of P2 primary rat cardiomyoblasts. However, pretreatment with nicardipine markedly decreased cell death in H2O2-treated primary rat cardiomyoblasts by regulating HO-1 protein expression. CONCLUSION: Nicardipine has a cardioprotective effect that helps maintain the viability of primary rat cardiomyoblasts with induced ischemic/reperfusion injury, including reactive oxygen species-induced damage.

Effects of H2O2 on Cardiac Rate and Apoptosis of Primary Rat Cardiomyoblasts in in Vitro Culture Systems

PURPOSE: This work was intended to establish experimental conditions for monitoring the effect of ischemic/reperfusion injury on the beating capability of and apoptotic damage to primary rat cardiomyoblasts. METHODS: In an in vitro system, cardiac rate differed depending on the number of days after birth that the cells were isolated. We maintained a mean rate of 62 times per min until 4 or 5 days in culture. To generate ischemic/reperfusion injury, primary rat cardiomyoblasts were treated with hydrogen peroxide (H2O2). RESULTS: Treatment with H2O2 significantly decreased the cardiac rate of primary rat cardiomyoblasts in a time- and dose-dependent manner. Interestingly, the cardiac rate of primary rat cardiomyoblasts abruptly dropped prior to the decrease in cell viability. H2O2 also induced a decrease in the expression of heme oxygenase-1 (HO-1) protein in P2 primary rat cardiomyoblasts in a time-dependent manner. Moreover, treatment with H2O2 resulted in an increase in the proportion of cells in the sub-G0/G1 phase, indicating that H2O2 induces the apoptotic death of P2 primary rat cardiomyoblasts. However, the intracellular level of calcium was markedly decreased under the same experimental conditions. CONCLUSION: An in vitro culture system is useful for investigating the mechanism underlying the beating capability of rat heart cells and the mechanism underlying apoptotic damage to primary rat cardiomyoblasts induced by ischemic/reperfusion injury, including ROS-induced damage.

Effects of H2O2 on Cardiac Rate and Apoptosis of Primary Rat Cardiomyoblasts in in Vitro Culture Systems

PURPOSE: This work was intended to establish experimental conditions for monitoring the effect of ischemic/reperfusion injury on the beating capability of and apoptotic damage to primary rat cardiomyoblasts. METHODS: In an in vitro system, cardiac rate differed depending on the number of days after birth that the cells were isolated. We maintained a mean rate of 62 times per min until 4 or 5 days in culture. To generate ischemic/reperfusion injury, primary rat cardiomyoblasts were treated with hydrogen peroxide (H2O2). RESULTS: Treatment with H2O2 significantly decreased the cardiac rate of primary rat cardiomyoblasts in a time- and dose-dependent manner. Interestingly, the cardiac rate of primary rat cardiomyoblasts abruptly dropped prior to the decrease in cell viability. H2O2 also induced a decrease in the expression of heme oxygenase-1 (HO-1) protein in P2 primary rat cardiomyoblasts in a time-dependent manner. Moreover, treatment with H2O2 resulted in an increase in the proportion of cells in the sub-G0/G1 phase, indicating that H2O2 induces the apoptotic death of P2 primary rat cardiomyoblasts. However, the intracellular level of calcium was markedly decreased under the same experimental conditions. CONCLUSION: An in vitro culture system is useful for investigating the mechanism underlying the beating capability of rat heart cells and the mechanism underlying apoptotic damage to primary rat cardiomyoblasts induced by ischemic/reperfusion injury, including ROS-induced damage.