Role of cytokine-induced neutrophil chemoattractant (CINC) in ozone- induced airway inflammation and hyperresponsiveness

Cytokine-induced neutrophil chemoattractant (CINC) is a rat chemokine with potent chemoattractant effects on neutrophils. We determined the involvement of CINC in ozone-induced airway neutrophilia and bronchial hyperresponsiveness (BHR) in the rat. We found a marked increase in lung CINC messenger RNA (mRNA) within 2 h after cessation of ozone exposure (1 ppm for 3 h), as measured by Northern blot analysis, whereas rats exposed to room air had no detectable CINC mRNA. Ozone exposure induced a significant neutrophilia in bronchoalveolar lavage fluid (BALF) at 24 h after exposure (air-exposed rats: 4.2 ± 2.0 x 10⁴, versus ozone-exposed rats: 16.1 ± 3.7 x 10⁴); prior treatment with a goat anti-CINC antibody (1 mg, intravenously) suppressed the neutrophilia (3.10.g x 10⁴). When administered intratracheally, the antibody (230 μg) partially inhibited the influx of neutrophils. The increase in bronchial responsiveness to acetylcholine observed after ozone exposure was not inhibited by the anti-CINC antibody. The anti-CINC antibody (1 mg, intravenously) also inhibited BALF neutrophilia induced by exposure to a higher concentration of ozone (3 ppm, 3 h), without an effect on BHR. CINC is an important chemokine causing ozone-induced neutrophil chemoattraction, but is not involved in the induction of ozone- induced BHR. The neutrophil is unlikely to contribute to BHR in this model.