Fig. 3

Examination of alveolar fibrosis in lung tissue. a Representative images of bleomycin-induced alternations in the alveolar interstitum and bronchial epithelium are shown using hematoxylin and eosin (HE) staining (×12.5 and ×200 images) and Elastica Masson (E-M) staining (×200 image). Extracellular matrix component proteins appear as blue–purple in E-M staining. Red arrows indicated particularly thick collagen bundles, which stain as black-purple bundles. Inhalation of hydrogen gas suppressed fibrous tissue production after lung injury. b Lung injury scores were low overall and not significantly different between treatment groups. c Ashcroft scores clearly demonstrated that there were more fibrotic changes in the lungs of the BA group as compared with the BH group. SA, saline administration and air inhalation, n = 6; SH, saline administration and hydrogen inhalation, n = 6; BA, bleomycin administration and air inhalation, n = 11, BH, bleomycin administration and hydrogen inhalation, n = 11. *p < 0.05; error bars indicate 95% CI