Effect of butyrate on the pulmonary histopathological changes of mice with ALI. Lung sections stained with hematoxylin-eosin from 24 hours after LPS administration revealed pulmonary histopathological changes (original magnification ×200). A. control group: normal structure. B. butyrate group: same as control group. C. LPS group: alveolar wall thickness, hemorrhage, alveolus collapse and obvious inflammatory cells infiltration. D. LPS + butyrate group: minor histopathological changes compared with LPS group.