Role Of LncRNA NANCI-NKX2.1 Signaling Pathway In Hyperoxia-induced Lung Injury In Neonatal Mice

[Objective]To investigate the expression pattern and role of long non-coding RNA NANCI-NKX2.1 signaling pathway in hyperoxia-induced lung injury.[Methods]1.Neonatal C57BL/6J mice were randomly divided into Control-Group and Hyperoxia-Group.We put the control group into pathogen-free rooms air(FiO2=21%),and exposed the hyperoxia group to oxygen box(FiO2>95%).The lung tissues were respectively collected after 7d,14d and 21d,8 mouse in each group.2.We observed lung tissue pathological changes by hematoxylin and eosin staining and calculate the Radial Alveolar Count(RAC)of each group,and RT-qPCR and Western blot were used to measure the mRNA and protein expression of NANCI and NKX2.1.3.We analyzed the datas and conclude the possible roles of NANCI-NKX2.1 signaling pathway in hyperoxia-induced lung injury.[Results]1.The lung pathology showed hyperoxia group have larger alveolar diameter,fewer numbers and thinner alveolar septum;their tracheal wall was thicker,inflammatory exudates were found in some of the airway and inflammatory cells infiltrated in the alveolar septum.With the hyperoxia exposure prolonged,alveolar septal rupture,inflammatory secretions and cell infiltration all increased.2.RAC:Compared with air group,the RACs in hyperoxia group significantly reduced(F=838.166,p<0.05),and there was respectively significant at the 3 time points between the two groups(7d:7.22±0.28 vs 4.98±0.42,p<0.001;14d:8.75±0.37 vs 4.47±0.63,p<0.001;21d:9.32±0.11 vs 4.09±0.16,p<0.001).RAC of air group gradually increased which was significant(F=103.831,p<0.05),and RAC of hyperoxia group gradually decreased which was significant(F=6.792,p<0.05).3.NANCI mRNA:Compared with air group,the NANCI in hyperoxia group significantly reduced(F=34.016,p=0.000),and there was respectively significant at the 3 time points between the two groups(7d:0.198±0.084 vs 0.058±0.040,p=0.002;14d:0.064±0.047 vs 0.018±0.012,p=0.026;21d:0.033±0.016 vs 0.002+0.001,p=0.001).The air group was the highest in 7 d(p<0.05),14 d and 21 d were not significant(p=0.276),and the high oxygen group gradually decreased which was significant(F=11.084,p=0.000).4.NKX2.1 mRNA:Compared with air group,the NKX2.1 in hyperoxia group significantly reduced(F=28.121,p=0.000),and there was respectively significant at the 3 time points between the two groups(7d:0.493±0.125 vs 0.322±0.127,p=0.017;14d:0.204±0.090 vs 0.047±0.024,p=0,001;21d:0.13 8±0.064 vs 0.034±0.020,p=0.002).The air group was the highest in 7 d(p<0.05),14 d and 21 d were not significant(p=0.183),and the high oxygen group gradually decreased which was significant(F=37.003,p=0.000).NKX2.1 protein:Compared with air group,the protein in hyperoxia group significantly reduced(F=66.743,p=0.000),and there was respectively significant at the 3 time points between the two groups(7d:1.58±0.14 vs 0.87±0.23,p=0.002;14±1.02±0.21 vs 0.61±0.07,p=0.010;21d:0.93±0.08 vs 0.55±0.08,p=0.001).The air group was the highest in 7 d(p<0.05),14 d and 21 d were not significant(p=0.609),and the high oxygen group gradually decreased which was significant(F=5.142,p=0.032).5.Correlation analysis showed the mRNA expression of NKX2 was positively correlated with NANCI(r=0.585,p=0.003).There was a positive correlation between NANC mRNA and RAC(r=0.655,p<0.05),and there was a positive correlation between NKX2.1 mRNA and RAC(r=0.541,P<0.05).[Conclusion]1.The lung injury and inflammatory reaction were more serious over the time of hyperoxia exposure.2.Downregulation of LncRNA NANCI/NEX2.1 signaling pathway might be involved in the pathogenesis of hyperoxia-induced lung injury in neonatal mice.