8-Isoprostane is an early biomarker for oxidative stress in chlorine-induced acute lung injury

Abstract

Inhalation of chlorine (Cl2) may cause oxidative acute lung injury (ALI) characterized by pulmonary edema, pneumonitis, and hyperreactive airways. The aim of the study was to identify possible biomarkers for Cl2-induced ALI.Female BALB/c mice were exposed to Cl2 for 15min using two protocols 1) concentration-dependent response (25–200ppm) and 2) time-kinetics (2h–14days post-exposure).Exposure to 50–200ppm Cl2 caused a concentration-dependent inflammatory response with increased expression of IL-1β, IL-6 and CXCL1/KC in bronchoalveolar lavage fluid 2–6h after exposure which was followed by increased lung permeability and a neutrophilic inflammation 12–24h post-exposure. The early inflammatory cytokine response was associated with a clear but transient increase of 8-isoprostane, a biomarker for oxidative stress, with its maximum at 2h after exposure. An increase of 8-isoprostane could also be detected in serum 2h after exposure to 200ppm Cl2, which was followed by increased levels of IL-6 and CXCL1/KC and signs of increased fibrinogen and PAI-1. Melphalan, a non-oxidizing mustard gas analog, did not increase the 8-isoprostane levels, indicating that 8-isoprostane is induced in airways through direct oxidation by Cl2. We conclude that 8-isoprostane represents an early biomarker for oxidative stress in airways and in the blood circulation following Cl2-exposure.