Role of p38 MAPK signal pathway in the expression of cycloxygenase-2 induced by lipopolysaccharide in human bronchial epithelial cells

Objective To investigate the effect of lipopolysaccharide (LPS) on the expression of cycloxygenase-2 (COX-2) in human bronchial epithelial cells (BEAS-2B),and the role of p38 mitogen-activated protein kinase (MAPK) signal pathway in the expression of COX-2 induced by LPS.Methods Human BEAS2B cells were treated for 2 hours with different concentrations of LPS (0,0.1,1,10,100 mg/L),and the expression levels of COX-2 were monitored with RT-PCR and dose-effect experiment was performed accordingly.Human BEAS-2B cells were treated with 10 mg/L LPS for 0,2,6,12 and 24 hours,and the expression levels of COX-2 were monitored with RT-PCR and dose-effect experiment was also performed.BEAS-2B cells were pretreated with 20 μmol/L SB203580 (p38 MAPK inhibitor) for 1 hour,and then exposed to 10 mg/L LPS for 2 hours.Effect of SB203580 on the expression of COX-2 was detected with RT-PCR.Results COX-2 expression tended to increase,when different concentrations of LPS treated BEAS-2B cells for 2 hours,with the expression level being obviously dose-dependent.After BEAS-2B cells were treated for 2 hours with 10 mg/L LPS,COX-2 expression reached peak,then decreased,and finally came to the basal level at 24 h.And no statistical significance could be noted,when it was compared with that of the control group (P ＜ O.05).p38 MAPK inhibitor,SB203580,could partially inhibit COX-2 expression induced by LPS in BEAS-2B cells.Conclusions LPS could induce the COX-2 expression in BEAS-2B cells in a dose-dependent manner,and the COX-2 expression reaches the peak at 2 h.p38 MAPK is involved in the COX-2 expression induced by LPS in BEAS-2B cells. Key words: Lipopolysaccharide;  Human bronchial epithelial cells;  Cycloxygenase-2;  SB203580