MiR-155-5p Regulates The Expression Of IL-6 And MIP-2 In Alveolar Macrophages On The Migration Of Neutrophils During Acute Lung Injury In Sepsis

Objective:To investigate the regulatory effect of miR-155-5P on the expression of IL-6 and MIP-2 in alveolar macrophages and the effect of neutrophils migration during acute lung injury in sepsis.Methods:Mouse alveolar macrophages(MH-S)were cultured and divided into control group,sepsis group and miR-155-5P inhibitor group.The miR-155-5P inhibitor group was transfected with miR-155-5P antagomir in advance.Lipopolysaccharide was used to intervene the sepsis group and miR-155-5P inhibitor group for 12 h.RT-PCR was used to detect the expressions of miR-155-5P,IL-6mRNA and MIP-2mRNA of alveolar macrophages in three groups,and ELISA was used to detect the concentrations of IL-6 and MIP-2 in cell suspension.Again,MH-S was divided into three groups and cultured in the lower compartment of Transwell plate.Neutrophils labeled with CFSE were cultured in the upper compartment.After Lipopolysaccharide intervention,fluorescence values of cells in the upper compartment and lower compartment were detected by flow cytometry,respectively,to calculate the migration rate of neutrophils.Results:Compared with the control group,the expression of miR-155-5P in alveolarmacrophages in the sepsis group was significantly up-regulated(P<0.05),the expression of IL-6mRNA and MIP-2mRNA were also significantly up-regulated(P<0.05),and the concentration of IL-6 and MIP-2 and the migration rate of neutrophils were significantly increased(P<0.05).The expression of miR-155-5P in the miR-155-5P inhibitor group was inhibited(P<0.05),the expression of IL-6mRNA and MIP-2mRNA,and the concentration of IL-6 and MIP-2 were all lower than those in the sepsis group(P<0.05)and higher than those in the control group(P<0.05).The migration rate of neutrophils was significantly lower than that in the sepsis group(P<0.05)and higher than that in the control group,but there was no statistical significance(P=0.528).Conclusion:In sepsis ALI,the expression of miR-155-5P gene in alveolar macrophages was highly expressed,and the expression of pro-inflammatory factors IL-6 mRNA and MIP-2 mRNA were also significantly up-regulated,which promoted the production of IL-6 and MIP-2,and caused a large number of chemotactic neutrophils to migrate into the lung,resulting in lung injury.However,inhibition of the expression of miR-155-5P can inhibit the production of IL-6 and MIP-2,thereby reducing the chemotactic migration of neutrophils and playing a protective role in lung.