The Effect Of MiRNA-21-5p On Early Apoptosis Of AEC? In Hyperoxic Acute Lung Injury By PTEN/Akt Pathway

Objective: To demonstrate mi RNA-21-5p can inhibite the early apoptosis of type ? alveolar epithelial cells(AEC?)in hyperoxic acute lung injury(HALI)by PTEN/Akt pathway by mi RNA-21-5p affects the early apoptosis of AEC? in HALI.Methods: The healthy male Sprague-Dawley rats were randomly divided into 4 groups(n = 6): CON group(control group: air feeding),H group(injury group: hyperoxia modeling),OE group(overexpression group: AAV-6 miRNA-21-5p was instilled into the lung of SD rats by intratracheal intubation and fed for 3 weeks,hyperoxia modeling),EV group(empty vector group: AAV-6 was instilled into the lung of SD rats by intratracheal intubation and fed for 3 weeks,hyperoxia modeling).The lung injury parameters were detected at 0h,24 h,48h and 60 h time points: oxygenation index(OI)and respiratory index(RI)of the carotid artery blood,wet/dry weight ratio of the left upper lobe,light microscopy and pathological scores of the left lower lobe.Real-time quantitative PCR(RT-qPCR)was used to detect mi RNA-21-5p and PTEN mRNA in AEC? at different time points.Western blot was used to detect PTEN protein and Akt/pAkt in AEC? at different time points.Flow cytometry(FCM)was used to detect the early apoptotic rate of AEC? at different time points in each group.Results: 1.The changes of OI: The OI gradually decreased with time at 4 time points in H group(P < 0.05).2.The changes of RI: The RI increased gradually at 4 time points in H group(P < 0.05).3.The changes of W/D weight ratios: The W/D weight ratios increased gradually at 4 time points in H group(P < 0.05).4.The light microscopy of the left lower lobe: In CON group,the neutrophils were occasionally observed in the alveolar space and interstitial space.In H group,the lung injury gradually increased with time.At 0h time point,the neutrophils were occasionally observed in the alveolar space and interstitial space.At 24 h time point,the neutrophils could be observed in the alveolar space and interstitial space.At 48 h time point,the neutrophils could be observed in the alveolar space and interstitial space,the proteinaceous debris could be observed and hyaline membranes could be occasionally observed in the airspaces.At 60 h time point,the neutrophils could be observed in the alveolar space and interstitial space,the proteinaceous debris and hyaline membranes could be observed in the airspaces,and the alveolar septal occasionally thickened.5.The changes of the pathological scores of the left lower lobe: The pathological scores of H group increased gradually with time(P < 0.05).6.The changes of miRNA-21-5p and PTEN mRNA were detected by RT-qPCR:(1)miRNA-21-5p: miRNA-21-5p was gradually increased at 4 time points in H group,OE group and EV group(P < 0.05).At 24 h,48h and 60 h,the miRNA-21-5p in H group and EV group was significantly higher than those in CON group(P < 0.05).At 4 time points,the miRNA-21-5p in OE group was significantly higher than those in H group(P < 0.05).(2)PTEN mRNA: PTEN mRNA gradually decreased with time at 4 time points in H group,OE group and EV group(P < 0.05).At 24 h,48h and 60 h,PTEN mRNA in H group and EV group was significantly lower than that in CON group(P < 0.05).At 4 time points,the miRNA-21-5p in OE group was significantly lower than those in H group(P < 0.05).7.The changes of PTEN protein and Akt/pAkt were detected by western blot:(1)PTEN protein: The expression of PTEN protein in H group,OE group and EV group gradually decreased with time(P < 0.05).Compared with CON group,in H group and EV group,the expression of PTEN protein was significantly lower(P < 0.05).At 4 time points,the expression of PTEN protein in OE group was significantly lower than that in H group(P < 0.05).(2)p-Akt/Akt: The expression of p-Akt/Akt in H group,OE group and EV group gradually increased with time(P < 0.05).Compared with CON group,in H group and EV group,the expression of p-Akt/Akt was significantly higher(P < 0.05).At 4 time points,the expression of p-Akt/Akt in OE group was significantly higher than that in H group(P < 0.05).8.The early apoptosis rate of AEC? was detected by FCM: The early apoptosis rate gradually increased with time at 4 time points in H group and EV group(P < 0.05),and gradually increased with time at 24 h,48h and 60 h in OE group(P < 0.05).At 24 h,48h and 60 h,compared with CON group,the early apoptosis rate in H group and EV group significantly increased(P < 0.05).At 24 h,48h and 60 h,the early apoptosis rate was significantly higher in OE group than that of H group(P < 0.05).Conclusions: miRNA-21-5p inhibited the early apoptosis of AEC? in HALI by PTEN/Akt pathway.