title: Comparison of aerosol and intranasal challenge in a mouse model of allergic airway inflammation and hyperresponsiveness.
abstract: BACKGROUND
  The aim was to optimize antigen challenge for induction of airway hyperresponsiveness (AHR) and inflammation in BALB/c mice sensitized to ovalbumin (OVA). Comparisons were made between mice challenged with OVA either as an aerosol or intranasally. The protocol that induced maximal AHR in BALB/c mice was thereafter tested in C57BL/6 mice.
  
  
  METHODS
  Methacholine responsiveness was measured using the flexiVent® system to assess AHR. Inflammatory responses were investigated by histology and cell counts in bronchoalveolar lavage (BAL) fluid.
  
  
  RESULTS
  48 h after challenge with 1 or 6% OVA aerosols, there were similar increments in AHR and BAL cells, predominantly eosinophils. When comparing the effect of 1% OVA aerosol on AHR and cell infiltration at 24 and 48 h after challenge, the responses were similar. At 24 h, intranasal OVA administration (20-200 μg) caused a dose-dependent increase in AHR. BAL cells were increased by all intranasal OVA doses and to a greater extent than after 1% OVA aerosol challenge but without any dose dependency. Histological examination confirmed that there was an increase of eosinophils in lung tissue following either challenge. In C57BL/6 mice, baseline tissue elastance was the only functional outcome that was increased after intranasal OVA challenge. Even though the AHR response was negligible in C57BL/6 mice, a similar infiltration of BAL cells was observed in both strains.
  
  
  CONCLUSIONS
  Intranasal challenge was more effective than aerosol challenge at inducing both AHR and airway inflammation in BALB/c mice. Although intranasal challenge caused airway inflammation in C57BL/6 mice, this strain is not optimal for studying AHR.
authors.affiliation: The National Institute of Environmental Medicine, Division of Physiology, and The Centre for Allergy Research, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Linda
authors.initials: L
authors.lastname: Swedin
authors.forename: Russ
authors.initials: R
authors.lastname: Ellis
authors.forename: Cecilia
authors.initials: C
authors.lastname: Kemi
authors.forename: Ake
authors.initials: A
authors.lastname: Ryrfeldt
authors.forename: Mark
authors.initials: M
authors.lastname: Inman
authors.forename: Sven-Erik
authors.initials: SE
authors.lastname: Dahlén
authors.forename: Mikael
authors.initials: M
authors.lastname: Adner
mesh_terms: D000281:Administration, Intranasal; D000336:Aerosols / Q000008:administration & dosage*; D000818:Animals; D016535:Bronchial Hyperreactivity / Q000139:chemically induced*; D004195:Disease Models, Animal; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D010047:Ovalbumin
chemical_list: D000336:Aerosols; D010047:Ovalbumin