XDH and acute kidney injury: When reperfusion and re-exposure to normal oxygen tension occurs, the increased XO activity and expression results in excessive production of ROS [5,7] Therefore, XO plays an important role in the OS-related tissue injury in all the diseases characterized by ischemia–reperfusion (H/R) conditions, including myocardial infarction, stroke, acute renal failure, and diseases affecting the maternal–fetal unit [7,8].