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

Cho, Tae Eun; Han, Yong Jae; Hwang, Yong; Yoo, Su Jin

Abstract

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.