title: Effects of repeated stress on distal airway inflammation, remodeling and mechanics in an animal model of chronic airway inflammation.
abstract: OBJECTIVE
  Epidemiological studies suggest that stress has an impact on asthmatic exacerbations. We evaluated if repeated stress, induced by forced swimming, modulates lung mechanics, distal airway inflammation and extracellular matrix remodeling in guinea pigs with chronic allergic inflammation.
  
  
  METHODS
  Guinea pigs were submitted to 7 ovalbumin or saline aerosols (1-5 mg/ml during 4 weeks; OVA and SAL groups). Twenty-four hours after the 4th inhalation, guinea pigs were submitted to the stress protocol 5 times a week during 2 weeks (SAL-S and OVA-S groups). Seventy-two hours after the 7th inhalation, guinea pigs were anesthetized and mechanically ventilated. Resistance and elastance of the respiratory system were obtained at baseline and after ovalbumin challenge. Lungs were removed, and inflammatory and extracellular matrix remodeling of distal airways was assessed by morphometry. Adrenals were removed and weighed.
  
  
  RESULTS
  The relative adrenal weight was greater in stressed guinea pigs compared to non-stressed animals (p < 0.001). Repeated stress increased the percent elastance of the respiratory system after antigen challenge and eosinophils and lymphocytes in the OVA-S compared to the OVA group (p < 0.001, p = 0.003 and p < 0.001). Neither collagen nor elastic fiber contents were modified by stress in sensitized animals.
  
  
  CONCLUSIONS
  In this animal model, repeated stress amplified bronchoconstriction and inflammatory response in distal airways without interfering with extracellular matrix remodeling.
authors: Department of Medicine, School of Medicine, University of São Paulo, São Paulo, Brazil.
authors: Edna A
authors: EA
authors: Leick
authors: Fabiana G
authors: FG
authors: Reis
authors: Flávia Alves
authors: FA
authors: Honorio-Neves
authors: Rafael
authors: R
authors: Almeida-Reis
authors: Carla M
authors: CM
authors: Prado
authors: Mílton A
authors: MA
authors: Martins
authors: Iolanda F L C
authors: IF
authors: Tibério
mesh_terms: D000280:Administration, Inhalation; D000311:Adrenal Glands / Q000473:pathology; D000704:Analysis of Variance; D000818:Animals; D004195:Disease Models, Animal; D005109:Extracellular Matrix / Q000378:metabolism; D006168:Guinea Pigs; D006967:Hypersensitivity / Q000209:etiology*; D007249:Inflammation / Q000139:chemically induced / Q000150:complications*; D008297:Male; D020556:Neutrophil Infiltration; D009929:Organ Size; D010047:Ovalbumin / Q000009:adverse effects; D010812:Physical Stimulation / Q000009:adverse effects; D012120:Respiration Disorders / Q000139:chemically induced / Q000150:complications* / Q000473:pathology*; D013315:Stress, Psychological / Q000473:pathology* / Q000503:physiopathology*; D013550:Swimming / Q000523:psychology
chemical_list: D010047:Ovalbumin