Figure 1

Lung histological data obtained on day 28. Increased fibrosis and collagen deposition occurred in the subpleural areas of the lungs of bleomycin (BLM)-treated mice compared with those in BLM-treated mice with pirfenidone administration and saline-treated control mice (A–H). Typical photomicrographs of hematoxylin and eosin (HE) and Masson trichrome staining of the right lungs from saline-treated and BLM-treated mice with or without pirfenidone. Magnification × 10. (I) The extent of lung fibrosis was quantified using quantitative histology according to Ashcroft’s method on day 28 to determine anti-fibrotic effects of pirfenidone in the lungs of BLM-treated mice. Because BLM administered with osmotic pumps causes lung fibrosis predominantly in subpleural regions, subpleural fibrosis between the groups was compared using a numerical scale. Pirfenidone administration significantly attenuated the numerical score increased by BLM treatment (*P < 0.0001). (J) The amount of collagen was quantified to determine the anti-fibrotic effects of pirfenidone in the lungs of BLM-treated mice. The collagen content in the lungs of BLM-treated mice was significantly increased compared with that in saline- or pirfenidone-treated mice, and this increase was significantly attenuated by pirfenidone administration on day 28 after BLM treatment (*P = 0.0012). Data are presented as means ± standard error. The experiment was repeated 3 times on different occasions with 6 mice per group. PFD, pirfenidone.