Regulation effects of naringin on diesel particulate matter-induced abnormal airway surface liquid secretion

Abstract Background PM2.5 is closely related to the incidence and mortality of respiratory diseases. Diesel particulate matter (DPM) is the main component of particulate air pollution and an important source of PM2.5. Hypothesis/purpose This study mainly explored the effect of DPM on airway surface liquid (ASL) secretion and the regulation of naringin in this process, to evaluate therapeutic potentials of naringin for the treatment of abnormal secretion of the respiratory tract caused by PM2.5. Methods The concentration of lysozyme was measured by Lysozyme Assay Kit. Total protein content was determined by the BCA Protein Assay Kit. The concentration of cAMP and MUC5AC, expressions of CFTR, AQP1, and AQP5 proteins were measured by ELISA. Expressions of CFTR, AQP1 and AQP5 mRNA were determined by qPCR. Amount of CFTR on the cell membrane was determined by immunofluorescence. Results The in vitro and in vivo studies had indicated that DPM could inhibit ASL secretion and increased the viscosity of the liquid. Naringin had the functions to attenuate DPM-induced injury, reduce liquid viscosity by reducing MUC5AC and total protein secretion, increase DPM-induced CFTR, AQP1, and AQP5 mRNA and protein expression, positively regulate apical CFTR insertion and promote CFTR activation by increasing intracellular cAMP. Conclusion These results demonstrated that naringin had regulating effects on the DPM-induced abnormal secretion of the respiratory tract.