Coronary Endothelium No‐Reflow Injury Is Associated with ROS‐Modified Mitochondrial Fission through the JNK‐Drp1 Signaling Pathway

Coronary artery no‐reflow is a complex problem in the area of reperfusion therapy, and the molecular mechanisms underlying coronary artery no‐reflow injury have not been fully elucidated. In the present study, we explored whether oxidative stress caused damage to coronary endothelial cells by inducing mitochondrial fission and activating the JNK pathway. The hypoxia/reoxygenation (H/R) model was induced in vitro to mimic coronary endothelial no‐reflow injury, and mitochondrial fission, mitochondrial function, and endothelial cell viability were analyzed using western blotting, quantitative polymerase chain reaction (qPCR), enzyme‐linked immunosorbent assay (ELISA), and immunofluorescence. Our data indicated that reactive oxygen species (ROS) were significantly induced upon H/R injury, and this was followed by decreased endothelial cell viability. Mitochondrial fission was induced and mitochondrial bioenergetics were impaired in cardiac endothelial cells after H/R injury. Neutralization of ROS reduced mitochondrial fission and protected mitochondrial function against H/R injury. Our results also demonstrated that ROS stimulated mitochondrial fission via JNK‐mediated Drp1 phosphorylation. These findings indicate that the ROS‐JNK‐Drp1 signaling pathway may be one of the molecular mechanisms underlying endothelial cell damage during H/R injury. Novel treatments for coronary no‐reflow injury may involve targeting mitochondrial fission and the JNK‐Drp1 signaling pathway.