Fig. 2. Growth of bacteria from fibrotic lung tissue cultured under hypersaline conditions and apoptosis induced by their culture supernatants.

a, b Computed tomography (CT) and CT fibrosis scoring of wild-type (WT) mice (n = 3) and TGFβ1 transgenic (TG) mice (n = 8). Bars indicate the means ± standard error of the means. Statistical analysis by two-tailed Wilcoxon signed rank test. *p = 0.01. c Fibrotic lung tissues excised under sterile conditions from wild-type (n = 3) and TGFβ1 transgenic (n = 8) mice were cultured in hypersaline culture media for 48 h. Analysis of bacterial colonies by transmission electron microscope. Scale bars indicate 100 nm. d Flow cytometry analysis of A549 alveolar epithelal cells cultured for 48 h in DMEM medium containing 1/10 diluted spent culture supernatant of the mixture of Staphylococcus spp. (strain 6; n = 9), Staphylococcus nepalensis strain CNDG (n = 9), or control medium (n = 9). Bars indicate the means ± S.D. Statistical analysis by two-tailed Mann–Whitney U test. *p < 0.0001. e Flow cytometry analysis of normal human bronchial epithelial cells cultured for 48 h in DMEM medium containing 1/10 diluted spent culture supernatant of the mixture of Staphylococcus spp. (strain 6; n = 8), Staphylococcus nepalensis strain CNDG (n = 8), or control medium (n = 4). Bars indicate the means ± S.D. Statistical analysis by two-tailed Mann–Whitney U test. *p < 0.005. f, g TUNEL assay was performed as described under methods after culturing A549 alveolar epithelial cells in the presence of medium (n = 6) or supernatant of Staphylococcus nepalensis strain CNDG (n = 6). Scale bars indicate 20 µm. Bars indicate the means ± S.D. Statistical analysis by two-tailed Mann–Whitney U test. *p < 0.01. Abbreviations are defined as HPF, high-power field; TUNEL, terminal deoxynucleotidyl transferase dUTP nick end labeling; DAPI, 4′,6-diamidino-2-phenylindole. The source data underlying 2b, d, e, g are provided in the Source Data file.