Role of ROS in emulsified isoflurane postconditioning-induced activation of Nrf2/ARE signaling pathway in rat cardiomyocytes / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the role of reactive oxygen species (ROS) in emulsified isoflurane postconditioning-induced activation of nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) signaling pathway in rat cardiomyocytes.Methods Primarily cultured cardiomyocytes of rats were divided into 4 groups (n =20 each) using a random number tablecontrol group (group C),hypoxia/reoxygenation (H/R) group,emulsified isoflurane postconditioning group (group EIP),and emulsified isoflurane postconditioning plus ROS scavenger N-2-mercaptopropionyl glycine (MPG) group (group EIP+MPG).Cardiomyocytes were exposed to the mixed air to establish the cardiomyocyte H/R damage model.Emulsified isoflurane (final concentration 1.68 mmol/L) was added at 45 min of hypoxia,and the cells were incubated for 5 min followed by restoration of oxygen supply for 60 min in group EIP.In group EIP+MPG,MPG (final concentration 2 mmol/L) was added at 5 min of incubation with emulsified isoflurane,the cells were incubated for 10 min,and the other treatments were similar to those previously described in group EIP.At the end of reoxygenation,the ultrastructure of cardiomyocytes was observed,and the damage to mitochondria was evaluated and scored,the intracellular free Ca2+ level and Nrf2 activity were measured,and the expression of Nrf2,heme oxygenase-1 (HO-1),superoxide dismutase 1 (SOD1) and quinine oxidoreductase 1 (NQO1) protein and mRNA was detected using real-time polymerase chain reaction and Western blot.Results Compared with group C,the mitochondrial damage score and intracellular free Ca2+ level were significantly increased,the Nrf2 activity was enhanced,and the expression of Nrf2,HO-1,SOD1 and NQO1 protein and mRNA was down-regulated in the other three groups (P＜0.05).Compared with group H/R,the mitochondrial damage score and intracellular free Ca2+ level were significantly decreased,the Nrf2 activity was enhanced,and the expression of Nrf2,HO-1,SOD1 and NQO1 protein and mRNA was up-regulated in group EIP and group EIP+MPG (P＜0.05).Compared with group EIP,the mitochondrial damage score and intracellular free Ca2+ level were significantly increased,the Nrf2 activity was weakened,and the expression of Nrf2,HO-1,SOD1 and NQO1 protein and mRNA was down-regulated in group EIP+MPG (P＜0.05).Conclusion The mechanism by which emulsified isoflurane postconditioning activates Nrf2/ARE signaling pathway may be related to ROS in rat cardiomyocytes.