Study of miR-146a and miR-155 expression in ear effusion of patients with secretory otitis media

Objective To investigate the expression levels and clinical significance of microRNA-146a （miR-146a） and microRNA-155 （miR-155） in the ear effusion of patients with secretory otitis media （SOM）. Methods A total of 58 SOM patients were assigned into the SOM group, and 30 healthy subjects were recruited into the control group. The expression levels of miR-146a and miR-155 in the plasma between two groups and in the auricular effusion in the SOM group were quantitatively measured by real-time fluorescence quantitative PCR. The expression levels of interleukin-2 （IL-2）, interferon-γ（IFN-γ）, interleukin-4 （IL-4） and interleukin-10 （IL-10） in the plasma between two groups and in the auricular effusion in the SOM group were measured by enzyme-linked immunosorbent assay （ELISA）. The correlation between miR-146a, miR-155, Th1 and Th2 proportion and Th1/Th2 was analyzed. Results Compared with the control group, the expression levels of miR-146a, miR-155, CD4 ⁺Th1, CD4 ⁺Th1, Th1/Th2, IL-2, IFN-γ, IL-4, IL-10, IFN-γ/IL-4 were significantly up-regulated in the SOM group （all P < 0.05）. Compared with plasma expression of the SOM group, the expression levels of miR-146a, miR-155, CD4 ⁺Th1, CD4 ⁺Th2, Th1/Th2, IL-2, IFN-γ, IL-4, IL-10, IFN-γ/IL-4 in the auricular effusion were up-regulated （all P < 0.05）.Pearson’s correlation analysis demonstrated that the expression levels of miR-146a and miR-155 were positively correlated with the proportion of CD4 ⁺Th1, CD4 ⁺Th2 and Th1/Th2. The expression levels of miR-146a and miR-155 were positively correlated with IL-2, IFN-γ, IL-4 and IL-10 in the auricular effusion. Conclusions The miR-146a and miR-155 are highly expressed in the ear effusion of SOM patients. The miR-146a and miR-155 can promote the progression of inflammation probably by affecting the balance of Th1/Th2.