In contrast, injection of 5-MTHF at a low dosage could further activate Nrf2 in the kidneys of rats after ischemia-reperfusion injury, leading to restoration of glutathione levels; injection of 5-MTHF also effectively restored SOD-1 expression and further increased HO-1 expression in the kidneys of rats with ischemia-reperfusion injury. This evidence concerns the gene HMOX1 and ischemia reperfusion injury.