Ablation Of Glutaredoxin 1 Promotes Pulmonary Angiogenesis And Alveolar Formation In Hyperoxia-injured Lungs By Modifying HIF-1A Stability And Inhibiting The NF-?B Pathway

Objective:Lung development requires microvessels to appear in the right number at the right time and place.Vascular development d isrupts the relationship between alveolar epithelium and capillaries is an important mechanism for the pathogenesis of BPD.In hyperoxia e nvironment,the Grx1/PSSG redox module regulates signal pathways a nd mediates pulmonary microvascular development.However,Grx1/PS SG's mode of action,function,and its relationship with BPD have n ot been fully elucidated.We speculate that under the oxidation state of BPD,Grx1/PSSG regulates the balance between inflammatory fact ors and VEGF through redox NF-kB and HIF-1?,thereby affecting p ulmonary vascular development,causing pathological changes in BPD and expanding alveolar septum.We intend to use mouse BPD mode l to explore the initiation factors of BPD:pulmonary microvascular d evelopment disorder-inflammatory mediator induction rather than VEG F-mediated physiological pulmonary microvascular developmental bloc k and pathological angiogenesis.Further clarify the mechanism of pul monary microangiogenesis disorder in the occurrence of BPD and att empt to treat BPD by interfering with the Grx1 signaling pathway.St rive to achieve a breakthrough in the vascular hypothesis of the path ogenesis of BPD and guide physiological capillary formation.Methods:C57BL/6 mice were included in the experiment within 24hours of birth.Crx1^-/-and WT mice were randomly divided into a control group(Grx^-/-control group and WT-control group)and an experimental group(Grx^-/-O2 group and WT-O2 group).85%hyperoxic model was used in this experiment.Lung tissue was collected after 1,3,7,14,and 21 days of hyperoxia.detect the protein expression and enzyme activity of Grx1;record the mortality of each group of mice in detail;observe the pathological changes of the lungs by HE,count the radial alveolar counts and the average alveolar intercept;detect the oxidative stress indicators of lung tissue:GSH/GSSG;western blot detection Protein expression of whole proteins VEGFA,VEGFR2,Bax,Bcl-2,caspase3,HIF-1?,p-p65and nuclear protein p65;q-PCR detection of MCP-1 and MIP-1?;immunofluorescence detection of Grx1,VEGFR2 in situ expression.Results:?1?The amount of Grx1 protein and enzyme activity in the lung tissue induced by hyperoxia increased,and compared with t he WT group.?2?The survival rates of 21-day-old mice in the WT air group,WT hyperoxia group,Grx1^-/-air group,and Grx1^-/-hypoxic group were 100%,30%,100%,and 55%,respectively.Compared wit h the air group,the hyperoxia group showed thickened or broken alv eolar space,enlarged alveolar space,inflammatory infiltration,and sig nificantly reduced alveolar number.Compared with the WT hyperoxia group,the Grx1^-/-hyperoxia group,the alveolar cavity decreased,the number of alveoli increased,and the alveolar structure tended to be normal.?3?The expression of VEGFA and VEGFR2 in the lung tiss ue of mice was significantly reduced after hyperoxia,and the express ion of VEGFA and VEGFR2 in the Grx1^-/-hypoxia group was increas ed compared with the WT hyperoxia group.?4?Compared with the WT hyperoxia group,the expressions of Bax and caspase3 in the Gr x1^-/-hypoxic group were significantly reduced,but the expression of Bcl-2 was not significantly different,and the ratio of Bax to Bcl-2was decreased.?5?Compared with the WT air group,the expression levels of macrophage chemokines MCP-1 and MIP-1?m RNA in the WT hyperoxia group were significantly increased;compared with the WT hyperoxia group,Grx1-/-hyperoxia MCP-1 and MIP-1?mRNA expression levels were significantly reduced in the group.?6?Compa red with the WT hyperoxia group,the expression of GSSG in the Gr x1^-/-hypoxic group increased,the ratio of GSH to GSSG increased,and oxidative stress was improved.?7?Compared with the WT air gr oup,the expression of whole protein p-p65 and nuclear NF-?B p65 p rotein in the WT hyperoxia group was significantly increased;compar ed with the WT hyperoxia group,the total protein p-p65 and nuclear NF-?B p65 protein expression in the Grx1^-/-hyperoxia group were s ignificantly reduced,while HIF-1?expression was significantly increa sed.Conclusion:After the knockout of Grx1,the lungs of neonatal are more resistant to hyperoxia.The protective mechanism may be that Grx1regulates pathological damage in hyperoxia by inhibiting NF-?B pathway and stabilizing HIF-1?pathway in vivo.