ABSTRACT
Objective To investigate the roles of theaflavins(TFs) in airway mucus hypersecretion induced by human neutrophil elastase(HNE). Methods Human lung adenocarcinoma cell A549 was stimulated by HNE for mucus hypersecretion,and TF monomers(TF1,TF2 and TF3) were used for intervention.The effects of TF monomers on viability of A549 cells were examined by MTT method.After the effective doses of TFs were determined,A549 cells were divided into 4 groups for experiment.In control group,A549 cells were cultured with serum-free medium.In HNE treatment group,A549 cells were treated with HNE(50 nmol/L) for 24 h.In TF monomer intervention groups,A549 cells were pre-treated with TF1,TF2 or TF3(50,100 or 200 ?g/mL) for 24 h,and were then treated with HNE for another 24 h.In AG1478 intervention group,A549 cells were pre-treated with AG1478(5 ?mol/L),an epidermal growth factor receptor blocker for 30 min,and were then treated with HNE for another 24 h.The changes in mucin(MUC) after treatment by different doses of TF1,TF2 and TF3,and by TF3(200 ?g/mL) for different time(12 h,24 h and 36 h) were detected.The changes in MUC5AC mRNA expression and MUC5AC protein expression were detected by RT-PCR and ELISA,respectively. Results The MUC5AC mRNA expression and protein expression in HNE treatment group were significantly higher than those in control group(P