Inhibiting Cytochrome C Oxidase Leads to Alleviated Ischemia Reperfusion Injury

Background and Objectives: The overall purpose of this study was to investigate the role of cytochrome C oxidase (CcO) in preventing ischemia reperfusion-induced cardiac injury through gaseous signaling molecule pathways. Materials and Methods: We used CcO inhibitor, potassium cyanide (KCN) to mimic the pre-treatment of gaseous signaling molecules in a global ischemia/reperfusion (IR) injury model in rats. Intracellular reactive oxygen species (ROS) was determined by measuring mitochondrial H2O2 and mitochondrial complex activity. Results: KCN pre-treatment led to decreased infarction area after IR injury and improved cardiac function. KCN pre-treated group challenged with IR injury was associated with reduced ROS production through inhibition of activity and not downregulation of CcO expression. In addition, KCN pre-treatment was associated with enhanced expression and activity of mitochondrial antioxidase, suggesting the role of CcO in regulating IR injury through oxidative stress. Conclusion: KCN pre-treatment reduced the severity of IR injury. The potential mechanism could be increased endogenous anti-oxidase activity and consequently, the enhanced clearance of ROS.