title: N-acetylcysteine exerts therapeutic action in a rat model of allergic rhinitis.
abstract: BACKGROUND
  The pathophysiologic mechanism of allergy is dependent on the action of many redox-sensitive proinflammatory mediators. However, even though redox disturbances are believed to be a hallmark of inflammation, little is known of the effect of redox imbalance to the pathophysiology of allergic rhinitis. We thus opted to investigate the relation of oxidative stress and allergic rhinitis, through the utilization of a potent antioxidant substance (N-acetylcysteine [NAC]) in a rat model of allergic rhinitis and the evaluation of its action on specific markers of inflammation.
  
  
  METHODS
  NAC (50 mg/kg and 250 mg/kg) was intraperitoneally administered to ovalbumin (OVA)-sensitized rats prior to intranasal challenge with OVA. Mucosal congregation of inflammatory cells (eosinophils and mast cells), mucosal expression of redox-sensitive enzymes (inducible nitric oxide synthase [iNOS] and cyclooxygenase 2 [COX-2]), and the blood levels of a key proinflammatory mediator (tumor necrosis factor-α [TNF-α]) were evaluated.
  
  
  RESULTS
  Intranasal OVA challenges lead to mucosal inflammation, induction of the mucosal expression of iNOS and COX-2 and elevation of TNF-α blood levels. NAC significantly inhibited accumulation of inflammatory cells and downregulated iNOS expression and TNF-α serum levels. The role of COX-2 appeared to be 2-fold and its expression was divergently modulated by NAC.
  
  
  CONCLUSIONS
  Our findings suggest that redox balance is involved in the pathophysiology of allergic rhinitis in rats and that NAC can potentially suppress the allergen-induced nasal inflammatory cascade. The investigation of the role of oxidative stress in atopy could help in the evaluation of the therapeutic potential of antioxidant substances in allergic diseases.
authors: Laboratory of Experimental Physiology, School of Medicine, Aristotle University, Thessaloniki, Greece. george.guibas@gmail.com
authors: George V
authors: GV
authors: Guibas
authors: Evangelia
authors: E
authors: Spandou
authors: Soultana
authors: S
authors: Meditskou
authors: Timoleon A
authors: TA
authors: Vyzantiadis
authors: Kostas N
authors: KN
authors: Priftis
authors: George
authors: G
authors: Anogianakis
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology / Q000627:therapeutic use*; D000281:Administration, Intranasal; D000485:Allergens / Q000008:administration & dosage; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology / Q000627:therapeutic use*; D000975:Antioxidants / Q000494:pharmacology / Q000627:therapeutic use*; D051546:Cyclooxygenase 2 / Q000276:immunology; D004195:Disease Models, Animal; D008297:Male; D009297:Nasal Mucosa / Q000276:immunology / Q000473:pathology; D052247:Nitric Oxide Synthase Type II / Q000276:immunology; D010047:Ovalbumin / Q000008:administration & dosage; D051381:Rats; D017207:Rats, Sprague-Dawley; D065631:Rhinitis, Allergic; D012221:Rhinitis, Allergic, Perennial / Q000188:drug therapy* / Q000276:immunology / Q000473:pathology; D014409:Tumor Necrosis Factor-alpha / Q000097:blood
chemical_list: D000485:Allergens; D000893:Anti-Inflammatory Agents; D000975:Antioxidants; D014409:Tumor Necrosis Factor-alpha; D010047:Ovalbumin; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D051546:Cyclooxygenase 2; C489691:Ptgs2 protein, rat; D000111:Acetylcysteine
keywords: N-acetylcysteine; TNF-α; allergic rhinitis; cyclooxygenase-2; experimental protocol; inflammation