Study on the Regulation of microRNA-124-3p on Lung Injury in Mice Infected with H1N1 Subtype Swine Influenza Virus

In order to study the regulatory effect of microRNA-124-3p(miR-124-3p) on lung injury caused by H1N1 subtype swine influenza virus (SIV) in mice,the expression vector of miR-124-3p adenovirus was constructed,and the miR-124-3p differentially expressed mouse models were induced by intravenous injection in the tail of mice which were divided it into three groups (overexpression,inhibition and control groups).48 h later,mice in each group were inoculated with H1N1 subtype SIV in the nasal cavity,with 10⁵ EID₅₀ (50 μL) per mouse.The average body weight change rate,pathological section observation and relative mRNA expression level of related inflammatory factors IL-1β,TNF-α and IL-6 in mice were observed for 14 consecutive days.The results showed that the pre-miR sequence and its sponge sequence had been successfully inserted into the shuttle plasmid of adenovirus,and co-transfected into 293A cells.Real-time PCR detection confirmed that compared with control group,the expression level of miR-124-3p in overexpression and inhibition groups were extremely significantly increased (P<0.01) and significantly decreased (P<0.05),respectively,indicating that the adenovirus expression vectors were successfully constructed.The rates of weight change of overexpression,inhibition and control groups were －5.5%,－12.4% and －8.6%,respectively.The alveolar wall of inhibition and control groups were thickened,in which there were a lot of lymphocyte infiltration,some of the alveoli showed fibrin exudation,and the pathological changes were more serious in the inhibition group,there were a lot of RBC infiltration in alveoli.There were only a little lymphocyte infiltration in overexpression group,and the lung tissue was normal.Compared with control group,the mRNA expression levels of IL-1β,TNF-α and IL-6 in overexpression group were significantly decreased (P<0.05);The mRNA expression levels of inflammatory factors in inhibition group were significantly increased (P<0.05).The results showed that miR-124-3p inhibited the expression of pulmonary inflammatory factors induced by H1N1 subtype SIV in mice,and also alleviated pathological injury of lung.