The Temporal Profile of Cytokines in the Bronchoalveolar Lavage Fluid in Mice Exposed to the Industrial Gas Phosgene

Abstract

Diagnosis of an exposure to airborne toxicants can be problematic. Phosgene is used widely in industry for the production of many synthetic products, such as polyfoam rubber, plastics, and dyes. Although nearly 100% of the gas is consumed during processing, there is the potential problem of accidental or even intentional exposure to this irritant/choking agent. Exposure to phosgene has been known to cause latent life-threatening pulmonary edema. A major problem is that there is a clinical latency phase from 3 to 24 h in people before irreversible acute lung injury occurs. Assessment of markers of acute lung injury after a suspected exposure would be useful in developing rational treatment strategies. These experiments were designed to assess bronchoalveolar lavage fluid (BALF) for the presence of the early markers of exposure to phosgene in mice from 1 to 72 h after exposure. Separate groups of 40 CD-1 male mice (Crl:CD-1(ICR)BR) weighing 29 ± 1 g were exposed whole-body to either air or a concentration × time (c × t) amount of 32 mg/m 3 (8 ppm) phosgene for 20 min (640 mg·min/m 3) . BALF from air- or phosgene-exposed mice was taken at 1, 4, 8, 12, 24, 48, and 72 h postexposure. After euthanasia, the trachea was excised, and 800 µl saline was instilled into the lungs and washed 5 ×. BALF was assessed for interleukin (IL)-4, IL-6, tumor necrosis factor (TNF)α, IL-1α, macrophage inflammatory protein (MIP)-2, and IL-10. At 4 h postexposure, IL-6 was 15-fold higher for phosgene-exposed mice than for the time-matched air-exposed control group. At 8 and 12 h, IL-6, IL-1β, MIP-2, and IL-10 were significantly higher in phosgene-exposed mice than in time-matched air-exposed controls, p ≤ .05 to p ≤ .001, whereas TNFα reached peak significance from 24 to 72 h. IL-4 was significantly lower in the phosgene-exposed mice than in the air-exposed mice from 4 to 8 h after exposure. These data show that BALF is an important tool in assessing pro- and anti-inflammatory markers of phosgene-induced acute lung injury and that knowledge of these temporal changes may allow for timely treatment strategies to be applied.