Modeling pulmonary fibrosis with bleomycin

Idiopathic pulmonary fibrosis is a chronic pulmonary disease of unknown origin ultimately leading to death. No treatment exists yet and animal models have been employed in order to elucidate its etiopathogenesis. Here, we summarize the characteristics of the bleomycin animal model, the most commonly used model of pulmonary fibrosis, highlighting recent advances it has led us to despite its disadvantages.Repetitive intratracheal administration of bleomycin more effectively mimics the chronic aspect of pulmonary fibrosis, as well as other characteristics including the presence of hyperplastic alveolar epithelial cells. Epithelial-to-mesenchymal transition seems to be a major contributor to the lung fibroblast population. There is growing evidence that macrophages, as well as fibrocytes, are largely involved in disease progression by mediating fibroblast and myofibroblast activation. In addition, molecules involved in phospholipid homeostasis are now becoming more appealing as potential therapeutic targets.Despite its disadvantages, the bleomycin animal model remains the best available experimental tool for studying disease pathogenesis and testing of novel pharmaceutical compounds. Two such compounds currently showing some promise in clinical trials have emerged through the bleomycin model and preliminary results of basic research using this model have shown that more candidate compounds may follow in the near future.