Interaction And Possible Mechanism Of Mitochondrial Aldehyde Dehydrogenase 2,Pyroptosis And Ferroptosis In A Sepsis-Induced Mouse Lung Injury Model

Objective:Observe the changes of pyroptosis and ferroptosis in a sepsis-induced mouse lung injury model,and to explore the possible effects of mitochondrial aldehyde dehydrogenase 2（ALDH2）on the mechanism of pyroptosis and ferroptosis in sepsisinduced lung injury model,further analysis of ALDH2,pyroptosis and ferroptosis three possible interactions.Methods:The model of lung injury in sepsis-induced mice was established by cecal ligation and puncture（CLP）,healthy male C57BL/6J mice were randomly divided into six groups: Sham group（Sham）,cecal ligation and puncture group（CLP）,dimethyl sulfoxide（DMSO）+CLP control group（DMSO+CLP）,NLRP3 inflammasome inhibitor MCC950+CLP group（MCC950+CLP）,ferroptosis inhibitor ferrostatin 1（Fer-1）+CLP group（Fer-1+CLP）,ALDH2 activator Alda-1+ CLP group（Alda-1+CLP）.At 24 hours after operation,the body weight and lung wet weight of mice in each group were measured and lung coefficients were calculated;The morphological changes of lung were observed by HE staining,and transmission electron microscope showed the ultrastructural changes of lung;The contents of MDA and iron in lung tissues were measured by kit,and the levels of reactive oxygen species（ROS）were measured by DHE fluorescence probe.Western blot was used to detect the expression of ALDH2 and4-HNE,pyroptosis-related proteins NLRP3,Caspase-1,GSDMD,Il-1β,IL-18,ferroptosis-related proteins GPX4 and PTGS2 also be examined.Results:Compared with sham group,the lung coefficient of CLP group was increased（P<0.05）;The lung tissue structure was seriously damaged（P<0.001）,neutrophils and mononuclear macrophages cell infiltration,mitochondrial structure rupture,volume reduction,lamellar body vacuolation;The content of MDA and iron in lung tissue increased significantly（P<0.001）;ROS level increased（P<0.001）;The expression of ALDH2 and GPX4 protein decreased（P<0.05）,Conversely,The expression of PTGS2,4-HNE and pyroptosis-related proteins NLRP3,Caspase-1,GSDMD and IL-1β,IL-18increased（P<0.05）.Compared with CLP group,the lung coefficient of MCC950+CLP,Fer-1+CLP,and Alda-1+CLP group was decreased（P<0.05）;The injury of lung tissue was reduced significantly（P<0.01）,neutrophils and mononuclear macrophages inflammatory cells infiltration decreases,and the injury of mitochondria and lamellar bodies was improved;The content of MDA and tissue iron decreased（P<0.05～0.001）;ROS levels decreased significantly（P<0.01）.The expression of ALDH2 and GPX4 protein increased（P<0.05）,and the expression of PTGS2,4-HNE and pyroptosisrelated proteins NLRP3,Caspase-1,GSDMD and IL-1β,IL-18 decreased（P<0.05）.Conclusion:In sepsis mice with lung injury,the expression of ALDH2 decreased,and pyroptosis and ferroptosis occurred at the same time;By activating mitochondrial ALDH2,inhibiting pyroptosis and ferroptosis,respectively,they can affect the level of oxidative stress,pyroptosis and ferroptosis in varying degrees,so as to play a role in lung protection;ALDH2,pyroptosis,and ferroptosis may interact during sepsis-induced lung injury.