Fig. 1.
HCl aspiration caused ARDS as well as elevated histone (nucleosome) levels in BALF and plasma of mice. (A) 0.1 N HCl was instilled intratracheally in mice and caused a significant decrease in PaO2 in a time-dependent manner (mean ± SD, n = 5–6 mice/group).*P < 0.01 vs. the sham group. (B) HCl aspiration caused a significant increase in lung wet–dry ratio of mice (mean ± SD, n = 5–6 mice per group).*P < 0.01 versus the sham group. (C) Hematoxylin and eosin–stained sections of lung damage at 6 h after HCl administration to mice. (a) sham-treated mice; (b) HCl-treated mice. Obvious pathological changes were observed in the lungs of HCl-treated mice, such as alveolar hemorrhage, infiltration of neutrophils. Scale bars: 100 μm. (D) BALF nucleosomes and (E) plasma nucleosomes were measured using ELISA in mice. (F) An example of histone H4 presence was detected by Western blot in the plasma of mice after HCl aspiration. The blots are representative of at least three independent experiments. (G) BALF histone H4 and (H) plasma histone H4 were measured using ELISA in mice. These levels were increased significantly after HCl aspiration in a time-dependent manner (mean ± SD, n = 5–6 mice per group). *P < 0.01 versus the shams. ARDS = acute respiratory distress syndrome; BALF = bronchoalveolar lavage fluid; ELISA = enzyme-linked immunosorbent assay; HCl = hydrochloric acid; PaO2 = partial oxygen tension.