Inhibitory effects of dexamethasone against polyinosinic: Polycytidylic acid-induced chemotactic factor expression in bronchial epithelial cells and the underlying mechanism / 第二军医大学学报

ABSTRACT

Objective To investigate the effect of dexamethasone on polyinosinic polycytidylic acid (PIC)-induced chemotactic factor expression in human bronchial epithelial (16hBE) cells and the underlying mechanism. Methods 16hBE cells were treated with different concentrations of PIC (0. 001, 0. 01, 0. 1, and 1 μg/ml) and dexamethasone (0.1, 1, and 10 μmol/L). IL-8 and IP-10 mRNA levels were detected by RT-PCR 6 h after stimulation. IL-8 and IP-10 protein levels in the culture supernatant were detected by ELISA 24 h after stimulation. NF-κB p65 subunit expression was detected by immunohistochemical staining. Results PIC concentration-dependently (0. 001, 0. 01, and 0. 1 μg/ml) increased the expression of IL-8 and IP-10 mRNA and protein compared with the control group, with significant differences found when PIC at 0.01 μ/ml and 0. 1 μ/ml (P<0. 05,P<0. 01). When the concentration of PIC was 1 μ/ml, the expressions of IL-8 and IP-10 were decreased at both mRNA and protein levels. Pretreatment with dexamethasone (1 μmol/L and 10 μmol/L) for 0. 5 h significantly inhibited the IL-8 and IP-10 expression at both mRNA and protein levels (P<0. 05, P<0. 01). Dexamethasone pretreatment (1 μmol/L) significantly inhibited PIC-induced NF-κB p65 subunit expression (P < 0. 01). Conclusion Glucocorticoids can suppress PIC-induced IL-8 and IP-10 expression in human bronchial epithelial cells, probably through activation of NF-κB pathway.