The Molecular Mechanism Of Antiapoptosis To Alveolar Type Ⅱ Epithelial Cell By MiR-21-5p

Objective: To observe the effect of miR21-5p on the TypeⅡalveolar epithelialcell(AEC-Ⅱ)apoptosis induced by H2O2and explore the molecular mechanism of itsanti-apoptotic.Methods: AEC-Ⅱ subculture ware divided into normal control group, H2O2injurygroup （0.5mmol/L H2O2continue training after injury）, miR-21-5p adenovirusoverexpressing group(miR-21-5p adenovirus vector transfected AEC-Ⅱ, after transfectionsuccess,0.5mmol/L H2O2induced apoptosis model), miR-21-5p negative transfectiongroup(free miR-21-5p adenovirus transfected AEC-Ⅱ, after a successful transfection,0.5mmol/L H2O2induced apoptosis model), Flow cytometry (FCM) in transfected6h,12h,24h,48h detection of early apoptosis rate, transmission electron microscopy (TEM) todetect apoptotic morphology,When transfected with48h Taq Man RT—PCR detectionAEC-Ⅱ of miR-21-5p levels and Western blot detection of Bcl-2, Bax, caspase-3levels.Result:(1) Identified AEC-Ⅱby TEM:Microvilli and osmiophilic multilamellar bodywere found,which are the characteristic structure of AEC-Ⅱ.(2) Detected apoptosismorphology by TEM:Cytoplamic etraction,chromation condensation and margination wereobserved,and microvilli and osmiophilic multilamellar body almost disappeared.(3) TaqMan RT—PCR to detect the AEC-Ⅱ of miR-21-5p levels: miR-21-5p overexpressiongroup compared with the levels of the other three groups of miR-21-5p was significantlyhigher (p <0.05).(4)Early apoptosis rate: Compared with normal control group, the otherthree groups apoptosis rate was gradually increased with the increase of injury time, H2O2injury group compared with the same time apoptosis rate point miR-21-5p overexpressionwas significantly lower than H2O2injury group (p <0.05), miR-21-5p negative controlgroup and H2O2injury group was no significant difference (p>0.05).(5) Western blot todetect the AEC-Ⅱ Bcl-2, Bax and caspase-3expression: the over-expression of miR-21-5p group Bax, caspase-3protein expression levels were significantly lower thanH2O2injury group (p<0.05), Bcl-2protein expression levels were significantly higherthan H2O2injury group (p <0.05)Conclution:(1) miR-21-5p have resistance to AEC-Ⅱ apoptosis effect (2) miR-21-5pas a new regulation target of AEC-Ⅱ apoptosis has potential application value.(3)adenoviral vector is a successful gene transfer vector when transfected with an AEC-Ⅱ.(4)miR-21-5p anti-AEC-Ⅱ apoptosis may through the mitochondrial pathway and reduceBax, caspase-3protein expression level and increase Bcl-2protein expression levels.