Quantifying the effect of pirfenidone treatment on bleomycin-induced pulmonary fibrosis mice model in vivo using a novel synchrotron-based imaging method

<bold>Background:</bold> We have developed a synchrotron-based x-ray diffraction enhance imaging (DEI)-based multiple-image radiography (MIR) imaging method to follow the progression of alveolar damage over time in bleomycin (BLM)-induced fibrosis in C57BL/6 mice <italic>in vivo</italic>. Here we investigated the anti-fibrotic effect of pirfenidone (PFD) under two conditions: treatment starting before BLM challenge (i.e. continuous), or starting from day 9 after BLM challenge, when fibrosis is established (i.e. therapeutic). <bold>Methods:</bold> Pulmonary fibrosis was induced by intratracheal administration of BLM (2.0 unit/kg). PFD treatment (30 mg/kg) was administered daily via oral gavage (n=6 for continuous, and n=7 for therapeutic); the effectiveness of the treatment was compared to a BLM, no treatment (n=16) and a phosphate-buffered saline (PBS) control group (n=6). <bold>Results:</bold> The continuous PFD treatment significantly prevented fibrosis formation. The therapeutic PFD treatment reduced the lung damage cause by BLM at week 2 and 3 after BLM challenge and accelerated the recovery of the mice (Fig 1). <bold>Summary:</bold> Synchrotron-based DEI-MIR provides a non-invasive quantitative assessment tool for testing the effect of current treatment for idiopathic pulmonary fibrosis (IPF) in small rodent models; and this imaging technique could be used for developing new treatments for the IPF patients. <fig><object-id>erj;64/suppl_68/PA858/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig>