Fig. 2.

Effect of low doses of RT on both lung tissue damages and immune cell infiltration in H1N1 pneumonia model. Mice were treated with PR8 influenza virus (H1N1) or PBS by intranasal instillation. After 2 days, mice were irradiated at the whole thorax at 0.5 Gy or 1 Gy or treated with dex. (A) Emphysem and alveolar septum rupture scoring 4 days after PR8 infection (left) and representative images (HES staining) of tissue lung from PR8-infected group (right). The arrows indicate emphysem. (B) Thickening of the alveolar septum scoring 4 days after PR8 infection (left) and representative images (HES staining) of tissue lung from the PR8-infected group (right). The double-pointed arrow indicates alveolar septum thickening. (C) Vascular congestion scoring in the lung tissue 8 days after PR8 infection (left) and representative images (HES staining) of tissue lung from the PR8-infected group (right). The arrow indicates vascular congestion. (D) Red blood cell extravasation scoring in the lung tissue 8 days after PR8 infection (left) and representative images (HES staining) of lung tissue from the PR8-infected group (right). The arrows indicate red blood cell extravasation. Data are from 2 independent experiments (n = 6-8). (E) Number of CD45+ cells, neutrophils, AMs, CD169- CD11c+ IMs, and NAMs in murine lungs 3 days after PR8 infection, analyzed by flow cytometry. Data are from 2 independent experiments (n = 6). For all data, bars indicate means and error bars indicate ±SEMs. *P < .05, **P < .01, ***P < .001, ****P < .0001 (1-way ANOVA). Abbreviations: AM = alveolar macrophage; ANOVA = analysis of variance; dex, dexamethasone; Gy = Gray; HES = hematoxylin-eosin-saffran; IM = interstitial macrophage; NAM = nerve- and airway-associated macrophage; PBS = phosphate-buffered saline; RT = radiation therapy; SEM = standard error of the mean.