The principal mechanism of ROS generation is the mitochondrial oxidative phosphorylation by cytochrome oxidase; other processes include the xanthine oxidase and NADPH oxidase complex, whereas the endothelial isoform of nitric oxide synthase (eNOS), and the AKI induced inducible nitric oxide synthase (iNOS) are the main source of NO production [122,123,124,125]. This evidence concerns the gene NOS2 and acute kidney injury.