Keratinocyte growth factor protects against Clara cell injury induced by naphthalene

Eur Respir J. 2008 Sep;32(3):694-704. doi: 10.1183/09031936.00155107. Epub 2008 Apr 2.

Abstract

Airway epithelial cells are exposed to environmental toxicants that result in airway injury. Naphthalene (NA) causes site-selective damage to Clara cells in mouse distal airways. N-terminally truncated recombinant human keratinocyte growth factor (DeltaN23-KGF) protects against acute lung injury. The present study investigated whether or not DeltaN23-KGF protects against NA-induced acute Clara cell damage by measuring airway responses specifically and in order to identify underlying molecular mechanisms. Mice were treated with DeltaN23-KGF or PBS 33 h prior to injection of 200 mg.kg body weight(-1) NA. Lung function was analysed by head-out body plethysmography. Distal airways isolated by microdissection were assessed for cell permeability using ethidium homodimer-1. Immunohistochemistry of Clara cell-specific protein in conjunction with a physical dissector was used to quantify Clara cell numbers. RNA was isolated from frozen airways in order to analyse gene expression using quantitative RT-PCR. DeltaN23-KGF prevented NA-induced airflow limitation and Clara cell permeability, and resulted in twice as many Clara cells compared with PBS pre-treatment. DeltaN23-KGF-pre-treated mice exhibited increased expression of proliferating cell nuclear antigen mRNA. Cytochrome P(450) isoform 2F2, which converts NA into its toxic metabolite, was reduced by approximately 50%. The present results demonstrate that pre-treatment with N-terminally truncated recombinant human keratinocyte growth factor protects against naphthalene-induced injury. This suggests that N-terminally truncated recombinant human keratinocyte growth factor exerts its beneficial effect through a decrease in the expression of cytochrome P(450) isoform 2F2.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Lung Injury / chemically induced
  • Acute Lung Injury / prevention & control*
  • Animals
  • Bronchioles / cytology
  • Bronchioles / drug effects*
  • Bronchioles / metabolism
  • Cytochrome P-450 Enzyme System / drug effects*
  • Cytochrome P-450 Enzyme System / metabolism
  • Disease Models, Animal
  • Epithelial Cells / drug effects*
  • Epithelial Cells / metabolism
  • Fibroblast Growth Factor 7 / administration & dosage*
  • Mice
  • Naphthalenes / toxicity
  • Plethysmography, Whole Body
  • Recombinant Proteins / administration & dosage*

Substances

  • Naphthalenes
  • Recombinant Proteins
  • Fibroblast Growth Factor 7
  • naphthalene
  • Cytochrome P-450 Enzyme System
  • Cyp2f2 protein, mouse