N-acetyl-L-cysteine inhibits bleomycin-induced interleukin-8 secretion by bronchial epithelial cells.

Bleomycin (BLM) has proven effective for the treatment of cancers, but the most serious dose-limiting side-effect is the development of pulmonary toxicity. Although the precise mechanism in the pathogenesis of BLM-induced lung injury has not been determined, oxygen radicals and neutrophils are indicated to play a key role in it. Interleukin-8 (IL-8) is thought to be an important mediator of the pathogenesis of acute lung injury. The IL-8 production from bronchial epithelial cell line, BEAS-2B cells was measured by enzyme-linked immunosorbent assays for IL-8. The concentrations of IL-8 were reportedly elevated in BLM-induced lung injury, suggesting the involvement of IL-8 in the pathogenesis of BLM-induced lung injury. In the present study, we showed that BLM induced the expression of IL-8 protein and mRNA in BEAS-2B cells, and N-acetyl-L-cysteine (NAC) inhibited IL-8 expression. In addition, the structurally unrelated antioxidant, pyrrolidine dithiocarbamate (PDTC) also effectively inhibited BLM-induced IL-8 production. These results suggest that anti-oxidant-sensitive mechanism might be involved in the inhibition of IL-8 secretion by BLM-stimulated bronchial epithelial cells and that NAC might be useful for the treatment of BLM-induced lung injury.