Study On Lung Morphology Development And Lung Surfactant Synthesis In MiRNA-26a Knock-out Mice

[Objectives]Normal formation and function of the lungs are essential for the transition of the fetus to an air-breathing environment at birth.The main purpose of the study was to explore the effect of miR-26a on lung development,by observing the morphological characteristics and studying the synthesis of pulmonary surfactant(PS)of miR-26a knockout mice lungs in different stages,and to provide some basis for the diagnosis and treatment of lung development related diseases.[Methods]According to the lung development stages of mice,the present study was concerned with three critical time points[embryonic day 16.5(E16.5),E18.5 and postnatal day 2(P2)].Hematoxylin-euphorbia(HE)and transmission electron microscopy were performed to observe the morphological characteristics of lung tissues.Immunochemistry(IHC),western blot(WB)and real-time PCR analysis were performed to examine the mRNA and protein levels of surfactant proteins.[Results ?HE results:Compared with wild type mice,more dilated and aerated lumens were observed in lungs of miR-26a knockout mice at E16.5.At E18.5,numerous AECIIs were produced and the alveolar structure of knockout mice lungs was more mature than that of wild type mice.More type II alveolar epithelial cells(AECIIs)and fewer type II alveolar epithelial cells(AECIs)were detected in lungs of knockout mice compared with wild type mice.?Transmission electron microscope results:Compared with wild type mice,increased intracellular glucogen was observed in miR-26a knockout mice lungs at E16.5 and increased mature lamellar bodies inside AECIIs were detected in miR-26a knockout mice at E18.5 and P2.?IHC?WB and realt-time PCR results:Compared with wild type mice,the expression of surfactant protein-A(SP-A)?SP-B and SP-C were significantly increased at both protein levels and mRNA levels in the miR-26a knockoutmice at E18.5 and P2.[Conclusions]Compared with wild type mice,knockout of miR-26a promotes the maturation in lung formation and increases the expression of surfactant proteins.Therefore,miR-26a has inhibitory effect on lung development and PS synthesis.