title: Effect of nitric oxide inhibitor and donor substances on the inflammatory process caused by endodontic irrigants.
abstract: Nitric oxide (NO) has been considered a key molecule in inflammation.
  
  
  OBJECTIVE
  The aim of this study was to evaluate the effect of treatment with L-NAME and sodium nitroprussiate, substances that inhibit and release NO, respectively, on tissue tolerance to endodontic irrigants.
  
  
  METHODS
  The vital dye exudation method was used in a rat subcutaneous tissue model. Injections of 2% Evans blue were administered intravenously into the dorsal penial vein of 14 male rats (200-300 g). The NO inhibitor and donor substances were injected into the subcutaneous tissue in the dorsal region, forming two groups of animals: G1 was inoculated with L-NAME and G2 with sodium nitroprussiate. Both groups received injections of the test endodontic irrigants: acetic acid, 15% citric acid, 17% EDTA-T and saline (control). After 30 min, analysis of the extravasated dye was performed by light absorption spectrophotometry (620 nm).
  
  
  RESULTS
  There was statistically significant difference (p<0.05) between groups 1 and 2 for all irrigants. L-NAME produced a less intense inflammatory reaction and nitroprussiate intensified this process.
  
  
  CONCLUSIONS
  Independently of the administration of NO inhibitors and donors, EDTA-T produced the highest irritating potential in vital tissue among the tested irrigating solutions.
authors.affiliation: Postgraduate Program in Dentistry, Department of Dentistry, University of Taubaté, Taubaté, SP, Brazil.
authors.forename: Luciana Malheiro de
authors.initials: LM
authors.lastname: Brito
authors.forename: Cláudia de Moura
authors.initials: Cde M
authors.lastname: Carreira
authors.forename: Denise Pontes
authors.initials: DP
authors.lastname: Raldi
authors.forename: José Luiz
authors.initials: JL
authors.lastname: Lage-Marques
authors.forename: Sandra Márcia
authors.initials: SM
authors.lastname: Habitante
authors.forename: Wilson Abraão
authors.initials: WA
authors.lastname: Saad
mesh_terms: D019342:Acetic Acid / Q000009:adverse effects; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D019343:Citric Acid / Q000009:adverse effects; D004492:Edetic Acid / Q000009:adverse effects; D004791:Enzyme Inhibitors / Q000627:therapeutic use*; D007249:Inflammation / Q000139:chemically induced / Q000188:drug therapy; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000627:therapeutic use*; D009569:Nitric Oxide / Q000037:antagonists & inhibitors*; D020030:Nitric Oxide Donors / Q000627:therapeutic use*; D009599:Nitroprusside / Q000627:therapeutic use*; D051381:Rats; D017208:Rats, Wistar; D012388:Root Canal Irrigants / Q000009:adverse effects*; D012965:Sodium Chloride / Q000009:adverse effects
chemical_list: D000893:Anti-Inflammatory Agents; D004791:Enzyme Inhibitors; D020030:Nitric Oxide Donors; D012388:Root Canal Irrigants; D009599:Nitroprusside; D019343:Citric Acid; D009569:Nitric Oxide; D012965:Sodium Chloride; D004492:Edetic Acid; D019342:Acetic Acid; D019331:NG-Nitroarginine Methyl Ester