Fig. 5

Involvement of oxidative stress in the expression of IL-33 in HBECs from COPD patients. a Effect of H₂O₂-potentiated IL-33 expression and reversal by NAC in human bronchial epithelial cells (HBECs) from healthy subjects. Cells were treated with NAC or vehicle prior to treatment with H₂O₂. After 4 h, whole cells were harvested and assayed for the IL-33 gene expression. b Effect of NAC on the expression of IL-33 in HBECs from healthy subjects and COPD patients. Cells were treated with NAC or vehicle. After 4 h, whole cells were harvested and assayed. The data are expressed as the mean ± SEM of five healthy subjects or six COPD patients. c-e Effect of p38-MAPK inhibitor (SB203580), JNK inhibitor (SP600125) or ERK inhibitor (U0126) on the expression of IL-33 in HBECs from COPD patients. Cells were treated with the MAPK inhibitor or vehicle. After 4 h, whole cells were harvested and assayed. The data is a representative of two independent experiments with four samples performed using HBECs from two COPD patients. **p < 0.01 compared with the values of vehicle-treated cells