[Retracted] Melatonin Attenuates Ischemia/Reperfusion‐Induced Oxidative Stress by Activating Mitochondrial Fusion in Cardiomyocytes
Xiaoling Ma, Sheng-Chi Wang, Hui Cheng, Haichun Ouyang, Xiaoning Ma
Abstract
Myocardial ischemia/reperfusion (I/R) injury can stimulate mitochondrial reactive oxygen species production. Optic atrophy 1‐ (OPA1‐) induced mitochondrial fusion is an endogenous antioxidative mechanism that preserves the mitochondrial function. In our study, we investigated whether melatonin augments OPA1‐dependent mitochondrial fusion and thus maintains redox balance during myocardial I/R injury. In hypoxia/reoxygenation‐ (H/R‐) treated H9C2 cardiomyocytes, melatonin treatment upregulated OPA1 mRNA and protein expression, thereby enhancing mitochondrial fusion. Melatonin also suppressed apoptosis in H/R‐treated cardiomyocytes, as evidenced by increased cell viability, diminished caspase‐3 activity, and reduced Troponin T secretion; however, silencing OPA1 abolished these effects. H/R treatment augmented mitochondrial ROS production and repressed antioxidative molecule levels, while melatonin reversed these changes in an OPA1‐dependent manner. Melatonin also inhibited mitochondrial permeability transition pore opening and maintained the mitochondrial membrane potential, but OPA1 silencing prevented these outcomes. These results illustrate that melatonin administration alleviates cardiomyocyte I/R injury by activating OPA1‐induced mitochondrial fusion and inhibiting mitochondrial oxidative stress.