Objective: To explore the correlation between the expression levels of miR-98-5p and the target protein STAT3 in alveolar lavage fluid of children with bronchial asthma and airway inflammation. Methods: A total of 120 children with bronchial asthma who were hospitalized or outpatient in our hospital from January 2017 to May 2020 were selected into asthma group, including 72 children in acute onset (BA-E group) and 48 children in remission (BA-R group), additional 20 children without bronchial asthma into control group. The bronchoalveolar lavage fluid samples (BALF) were collected and detected for miR-98-5p, STAT3 and airway inflammatory factors (IL-6, IL-10, IL-13, TNF-α, IgE). The lung function and the content of FeNO were also detected. Results: Compared with the control group, the relative expression of miR-98-5p in the BALF samples of children with asthma in the two sub-groups decreased, and the level of STAT3 increased, and the changes in the levels of miR-98-5p and STAT3 in the BA-E group were more obvious (P<0.05). TargetScan online software and dual luciferase reporter gene analysis proved that miR-98-5p has a complementary sequence binding to STAT3 mRNA. Compared with children in the BA-R group, the levels of IL-10 in the FEV1, FEV1/FVC and BALF samples in the BA-E group decreased, while the levels of IL-6, IL-13, TNF-α, and IgE in FeNO and BALF increased (all P<0.001). According to Pearson analysis, miR-98-5p was negatively correlated with STAT3, IL-6, IL-13, TNF-α, and IgE(all r<0,P<0.001). There was a positive correlation with IL-10 level (r=0.288,P=0.001); while the STAT3 level in BALF was positively correlated with IL-6, IL-13, TNF-α, and IgE(all r>0,P<0.001), and was negatively correlated with IL-10 level (r=-0.285, P<0.001). Conclusion: The relative expression of miR-98-5p in BALF of asthmatic children decreases, while the level of STAT3 protein increases, which is related to airway inflammation.
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