Role Of Anion Exchanger-3(ae3) In Ischemic Preconditioning Of Cardiomyocytes

Objective: The purpose of this study is to investigate effects of AE3 protein and its signal mechanisms in anoxia preconditioning of normal and AE3 expression down-regulated H9c2 cells.Methods: Cultured H9c2s were cultured in a 6-well culture plate uniformly and were randomly divided into five groups, namely, Control group, Non-silencing shRNA group, Anoxia/Reoxygenation group, Anoxia Preconditioning group and RNAi + Anoxia Preconditioning group. Cell viability, expression levels of AE3 mRNA and protein, apoptosis of H9c2s, intracellular level of ROS, activities of SOD and GSH-Px, concentration of Ca2+ and Cl- were detected.Results: After Anoxia/Reoxygenation, the cell viability was significantly decreased, and the expression levels of AE3 mRNA and its protein were significantly increased, compared to control group(p<0.01). Moreover, comparing with control group, it was also found that the ROS, apoptosis and concentration of Ca2+ and Cl- were increased, while, activities of SOD and GSH-Px were decreased(p<0.01). Under Anoxia Preconditioning condition, the expression levels of AE3 mRNA and its protein were increased, meanwhile, the cell viability, the activities of SOD and GSH-Px were increased significantly compared with anoxia/Reoxygenation group. While ROS and apoptosis were decreased compared with A/R group(p<0.01). Downregulation of AE3 expression by its gene-silencing could abolish these changes and there were significant difference between RNAi group and APC group(p<0.01). However, the results from the Non-silencing shRNA group were as similar as those from the control group and there was no significant difference between the two groups (p>0.05).Conclusion: AE3 plays an important role in anoxia preconditioning against anoxia/reoxygenation injury by inhibiting A/R-induced increase of [Cl-]i and ROS, and subsequently inhibiting A/R-induced oxidative stress, Ca2+ overload, and cell apoptosis.