title: Intratracheal bleomycin causes airway remodeling and airflow obstruction in mice.
abstract: In addition to parenchymal fibrosis, fibrotic remodeling of the distal airways has been reported in interstitial lung diseases. Mechanisms of airway wall remodeling, which occurs in a variety of chronic lung diseases, are not well defined and current animal models are limited. The authors quantified airway remodeling in lung sections from subjects with idiopathic pulmonary fibrosis (IPF) and controls. To investigate intratracheal bleomycin as a potential animal model for fibrotic airway remodeling, the authors evaluated lungs from C57BL/6 mice after bleomycin treatment by histologic scoring for fibrosis and peribronchial inflammation, morphometric evaluation of subepithelial connective tissue volume density, TUNEL (terminal deoxynucleotidyl transferase dUTP-mediated nick-end labeling) assay, and immunohistochemistry for transforming growth factor β1 (TGFβ1), TGFβ2, and the fibroblast marker S100A4. Lung mechanics were determined at 3 weeks post bleomycin. IPF lungs had small airway remodeling with increased bronchial wall thickness compared to controls. Similarly, bleomycin-treated mice developed dose-dependent airway wall inflammation and fibrosis and greater airflow resistance after high-dose bleomycin. Increased TUNEL(+) bronchial epithelial cells and peribronchial inflammation were noted by 1 week, and expression of TGFβ1 and TGFβ2 and accumulation of S100A4(+) fibroblasts correlated with airway remodeling in a bleomycin dose-dependent fashion. IPF is characterized by small airway remodeling in addition to parenchymal fibrosis, a pattern also seen with intratracheal bleomycin. Bronchial remodeling from intratracheal bleomycin follows a cascade of events including epithelial cell injury, airway inflammation, profibrotic cytokine expression, fibroblast accumulation, and peribronchial fibrosis. Thus, this model can be utilized to investigate mechanisms of airway remodeling.
authors.affiliation: Department of Medicine, Division of Allergy, Pulmonary and Critical Care Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-2650, USA. vasiliy.v.polosukhin@vanderbilt.edu
authors.forename: Vasiliy V
authors.initials: VV
authors.lastname: Polosukhin
authors.forename: Amber L
authors.initials: AL
authors.lastname: Degryse
authors.forename: Dawn C
authors.initials: DC
authors.lastname: Newcomb
authors.forename: Brittany R
authors.initials: BR
authors.lastname: Jones
authors.forename: Lorraine B
authors.initials: LB
authors.lastname: Ware
authors.forename: Jae Woo
authors.initials: JW
authors.lastname: Lee
authors.forename: James E
authors.initials: JE
authors.lastname: Loyd
authors.forename: Timothy S
authors.initials: TS
authors.lastname: Blackwell
authors.forename: William E
authors.initials: WE
authors.lastname: Lawson
mesh_terms: D000402:Airway Obstruction / Q000139:chemically induced* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D056151:Airway Remodeling / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000008:administration & dosage / Q000633:toxicity; D001761:Bleomycin / Q000008:administration & dosage / Q000633:toxicity*; D004195:Disease Models, Animal; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D005260:Female; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D006801:Humans; D054990:Idiopathic Pulmonary Fibrosis / Q000139:chemically induced* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D007249:Inflammation / Q000139:chemically induced / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D008168:Lung / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D000071999:S100 Calcium-Binding Protein A4; D009418:S100 Proteins / Q000235:genetics / Q000378:metabolism; D053773:Transforming Growth Factor beta1 / Q000235:genetics / Q000378:metabolism; D053781:Transforming Growth Factor beta2 / Q000235:genetics / Q000378:metabolism
chemical_list: D000903:Antibiotics, Antineoplastic; D000071999:S100 Calcium-Binding Protein A4; D009418:S100 Proteins; C470944:S100a4 protein, mouse; D053773:Transforming Growth Factor beta1; D053781:Transforming Growth Factor beta2; D001761:Bleomycin