[Effects of erythromycin on hydrogen peroxide-induced interleukin-8 synthesis and regulation of glutathione in human bronchial epithelial cells].

OBJECTIVE

To study the effects of erythromycin on Hydrogen peroxide (H2O2)-induced interleukin-8 synthesis and regulation of glutathione in human bronchial epithelial cells.

METHODS

Human bronchial epithelial (16HBE) growth curve was recorded by MTT, cells were divided into three groups (1) control (incubation for 24, 36, 48) (2) H2O2 (Pre-incubation for 24, 36, 48 h before adding H2O2 (3) H2O2 + EM (Pre-incubation EM for 24, 36, 48 h before adding H2O2). IL-8 levels were measured in culture supernatants by ELISA, activation of transcription factor NF-kappaB and AP-1 in HBE was evaluated by Electrophoretic mobility shift assay (EMSA). Intracellular GSH and Gamma-GCS concentrations were measured by spectrophotometric assay, gamma-GCS-HS protein were determined by Western blot.

RESULTS

Erythromycin (1 microg/ml, 10 microg/ml) and H2O2 (0.01 mM, 0.1 mM) have no effects on cell growth, Preincubation with EM (5 microg/ml) for 36 h and 48 h significantly inhibit H2O2 (0.01 mmol/L) induced increase of IL-8 levels in HBE supernatants, in the mean time decrease the expression of NF-kB and AP-1. Preincubation with EM (5 microg/ml) for 48 h significantly inhibit H2O2 (0.01 mmol/L) induced increase of gamma-GCS levels, gamma-GCS-HS protein expression and AP-1 binding of gamma-GCS-HS promoter in HBE. However GSH and gamma-GCS-HS protein expression in EM + H2O2 group significantly higher than those in control group.

CONCLUSION

Erythromycin inhibits oxidant-mediated IL-8 levels through down-regulation of NF-kB and AP-1 binding in HBE, which can further influence the synthesis of GSH and expression gamma-GCS in HBE.