Fig. 5

Histopathological changes of lung tissue in mice at the end point of the experiment (HE staining, ×200). BLM (5 mg/kg) intratracheally administered once for 2 weeks and then treated with pirfenidone (300 mg/kg/d orally administered) for 4 weeks. Lung histological data obtained on day 14 after BLM treatment and day 42 after PFD treatment (BLM 42 d). a: Lung inflammation, fibrosis, and integrity of the structure was evaluated by H&E (×200). Degree of fibrosis in lung tissues by Masson’s staining (×200). b and c: Degree of lung fibrosis was evaluated by inflammation and fibrosis scored. The data are expressed as mean ± SD,*P < 0.05, **P < 0.01, vs. BLM 14d and 42 d group