Fig. 1.

Low doses of RT protect mice from LPS-induced pneumonia and increase IL-10 production by NAMs. Mice were treated with LPS or PBS by intratracheal administration for 2 consecutive days. At 6 hours after the second intratracheal administration, mice were irradiated at the whole thorax at 0.5 Gy or 1 Gy. (A) CT scans of lung density in different treatment groups 24 hours and 96 hours after the first dose of LPS (left) and lung density (HU) quantification in the different treatment groups 96 hours after the first dose of LPS (right). Data are from 3 independent experiments (n = 10-11). (B) Representative images (HES staining) of lungs from LPS-treated mice (left; scale bar = 1 mm) and scoring of the destruction of the parenchyma (right) 96 hours after the first dose of LPS. (C) Scoring of the peribronchial infiltrate. Data are representative of 2 independent experiments (n = 6-7). (D and E) At 18 hours after irradiation, the percentages of IL-10+ NAMs are presented for each treatment group (left), and representative histograms of the fluorescence associated with IL-10 in NAMs are shown for each treatment group (right). Data were obtained from 2 independent experiments (n = 7-8). For all data, bars indicate means and error bars indicate ±SEMs. *P < .05, ****P < .0001 (1-way ANOVA). Abbreviations: ANOVA = analysis of variance; CT = computed tomography; FMO = fluorescence minus one; Gy = Gray; H&E = hematoxylin and eosin; HES = hematoxylin-eosin-saffran; HU = Hounsfield Unit; IL = interleukin; LPS = lipopolysaccharide; NAM = nerve- and airway-associated macrophage; PBS = phosphate-buffered saline; RT = radiation therapy; SEM = standard error of the mean.