6.1.1 Antioxidant
The massive production of ROS during reperfusion is the main cause of a series of oxidative stress responses, however, H2S can inhibit its production by regulating ROS signaling pathways, such as inhibiting NF-κB and JAK2-STAT3 pathways to reduce ROS levels[113].At the same time, H2S can also increase the expression levels of superoxide dismutase (SOD) and glutathione (GSH) in I/R tissues, both of which are antioxidant enzymes that protect cardiomyocytes by converting peroxides (H2O2)[74, 114]. In addition H2S can promote nuclear translocation of nuclear factor-E2-related factor-2 (Nrf2), an important antioxidant transcription factor that increases transcription of antioxidant proteins and reduces apoptosis and mitochondrial damage[115].