title: Effect of nedocromil sodium on allergen-induced airway responses and changes in the quantity of airway smooth muscle in rats.
abstract: BACKGROUND
  Allergen exposures induce growth of airway smooth muscle in the Brown Norway rat.
  
  
  OBJECTIVE
  The purpose of the study was to examine the role of mediators associated with the early and late responses in the induction of airway smooth muscle growth.
  
  
  METHODS
  Nedocromil sodium was administered to block early and late responses in ovalbumin-sensitized and ovalbumin-challenged rats undergoing single or multiple challenges (5 times at 5-day intervals) with ovalbumin. Airway smooth muscle was quantitated by morphometry on lungs removed 2 days after the final challenge.
  
  
  RESULTS
  Nedocromil sodium administered before ovalbumin challenge blocked both the early and late responses. When administered 2 hours after ovalbumin challenge, it also blocked the late response. Rats undergoing challenge with aerosolized ovalbumin five times at 5-day intervals were also treated with nedocromil before (n = 10) or 2 hours after (n = 10) each ovalbumin inhalation, respectively. The quantity of airway smooth muscle standardized for size was greater after ovalbumin challenge (0.069 +/- 0.005) compared with saline controls (0.033 +/- 0.003, p < 0.005). Nedocromil significantly reduced the airway smooth muscle (0.036 +/- 0.003, p < 0.005) when administered before ovalbumin. However, the airway smooth muscle in rats that received nedocromil 2 hours after ovalbumin challenge (0.046 +/- 0.003), although lower than in ovalbumin-challenged rats (p < 0.01), was still significantly higher than in saline-treated rats (p < 0.05).
  
  
  CONCLUSIONS
  Allergen-induced early responses, late responses, and airway inflammation are antagonized by nedocromil. The mediators of both the early and late responses contribute to allergen-induced airway smooth muscle growth, a process that can be prevented by administration of nedocromil.
authors: Meakins-Christie Laboratories, Royal Victoria Hospital, McGill University, Montreal, Quebec, Canada.
authors: T
authors: T
authors: Du
authors: S
authors: S
authors: Sapienza
authors: C G
authors: CG
authors: Wang
authors: P M
authors: PM
authors: Renzi
authors: R
authors: R
authors: Pantano
authors: P
authors: P
authors: Rossi
authors: J G
authors: JG
authors: Martin
mesh_terms: D000485:Allergens / Q000187:drug effects / Q000494:pharmacology*; D000818:Animals; D016535:Bronchial Hyperreactivity / Q000473:pathology / Q000503:physiopathology*; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D002455:Cell Division / Q000187:drug effects; D005260:Female; D007962:Leukocytes / Q000473:pathology; D008297:Male; D009130:Muscle, Smooth / Q000187:drug effects* / Q000473:pathology; D017835:Nedocromil / Q000494:pharmacology*; D010047:Ovalbumin / Q000187:drug effects / Q000494:pharmacology; D051381:Rats; D011914:Rats, Inbred BN
chemical_list: D000485:Allergens; D017835:Nedocromil; D010047:Ovalbumin