The Expression Of MicroRNA-125b After Nrf2 Suppressed By SiRNA In A549 Cells Exposed To Hyperoxia And Its Relationship With Apoptosis

Part 1 The expression of Nrf2 and micro RNA-125 b in lung tissue cells of premature rats exposed to hyperoxiaObjective To observe the expression of nuclear transcription factor E2-related factor 2(Nrf2)and micro RNA-125b(mi R-125b)in lung tissues of premature SD rats exposed to hyperoxia,and explore the relationship between mi R-125 b and Nrf2 in bronchopulmonary dysplasia(BPD)of neonate.Methods Eighty premature SD rats of 21 days gestational age were randomly divided into two groups: air group and hyperoxia group,with 40 rats in each group.The premature rats in the air group was housed in the room at air under atmospheric pressure(Fraction of inspiration O2,Fi O2 = 21%)and the premature rats in the hyperoxia group were placed in the same room at atmospheric pressure with self-made oxygen box(size 90×60×50cm,Fi O2 > 80%,humidity 60-70%,and carbon dioxide concentration<0.5%).Lung tissue samples were collected from two groups at 1,4,7,10 and 14 days.The expression of Nrf2 and mi R-125 b in lung tissue of premature rats was detected by real-time fluorescence quantitative reverse transcription polymerase chain reaction(RT-q PCR).Results(1)Compared with the air group,the Nrf2 of premature neonatal rats in the hyperoxia group at d1 and d7 with statistical significance(p< 0.05),and increased gradually at d7,but there was no statistical significance on the d4,d10,d14(p<0.05).(2)Compared with the air group,the expression trend of mi R-125 b after hyperoxia exposure was similar to that of Nrf2,which increased significantly at the d1,d4,d7,and decreased significantly at d10 and d14,with statistical significance(p < 0.05).Conclusions Exposed to hyperoxia leads to changes in the expression of Nrf2 and mi R-125 b in lung tissue of premature neonatal rats,suggesting that both Nrf2 and mi R-125 b are involved in the development of hyperoxia-induced lung injury.Part 2 The expression of micro RNA-125 b after Nrf2 suppressed by si RNA in A549 cells exposed to hyperoxia and its relationship with apoptosisObjective To observe the expression of mi R-125 b and its relationship with apoptosis in A549 cells exposed to hyperoxia ager si RNA inhibit Nrf2,and explore the relationship between mi R-125 b,Nrf2 and BPD.Methods The expression of Nrf2 in A549 cells was blocked by small interfering RNA(si RNA).These cells were randomly divided into four groups,air group without interference,hyperoxia group without interference,air group after interference,and hyperoxia group after interference.Hyperoxia group was exposed to oxygen(92% O2,5% CO2)while air group was in room air(5% CO2).After exposed to oxygen or room air for 48 hours,RNA of cells was isolated.mi R-125 b was detected by RT-q PCR.Flow cytometry was used to detect the apoptosis of A549 cells after Nrf2 silencing at different time points exposed to oxygen.Results(1)Compared with air group without interference,the expression of Nrf2 and mi R-125 b in hyperoxia group without interference was significantly increased(p < 0.05)exposed to oxygen after 48 hours.Compared with air group after interference,the expression of Nrf2 did not change significantly in the hyperoxia group after interference(T = 0.070,P = 0.804),and the expression of mi R-125 b decreased significantly(T = 7.891,P < 0.05)exposed to oxygen after 48 hours.(2)The apoptotic percentage of A549 cells in the hyperoxia group after Nrf2 suppressed by si RNA,increased significantly at 24 hours,48 hours and 72 hours(p < 0.05),which were(28.20 ±1.13)%,(31.95±0.21)%,(38.45 ±0.21)%)respectively.Conclusions The apoptosis of A549 cells exposed to hyperoxia significantly increased after Nrf2 suppressed by si RNA,which caused oxidative damage.mi R-125 b as a downstream target of Nrf2,are involved in the development of BPD.