title: Effects of n-acetylcysteine on ischemic preconditioning: study in isolated rat hearts.
abstract: OBJECTIVE
  The aim of this study is to assess if N-Acetylcysteine (NAC) changes the Ischemic Preconditioning (IP) in isolated rat hearts using only one cycle of IP.
  
  
  METHODS
  Heart Rate (HR), Coronary Flow (CF) and Myocardial Contractility (dP/dt) were registered in 30 Wistar rat's hearts. After anesthesia the hearts were removed and perfused with Krebes-Hensleit equilibrated solution with 95% of O2 and 5% of CO2 according Langendorff's method. GI: Control (n=6); GII: 20 min. ischemia (n=6); GIII: IP (n=6); GIV 50 microg/ml/min NAC before IP (n =6); GV: 100 microg/ ml/min NAC before IP (n=6). Parameters were measured after 15 min. of stabilization (T 0) and T3, T5, T10, T15, T20, T25 and T30 min. after reperfusion. Statistical significance was considered when P<0.05.
  
  
  RESULTS
  There were changes on HR comparing GI with GII at T20 and T25 and comparing GI with GIII, GIV with GV at T10 and T20 (P<0.05). CF was different comparing GI with GII at T3 and T5, GI with GIV at T10 and GI with GV at T10 and T25 (P<0.05). Myocardial Contractility was similar comparing GIII with GI and GV. GIII had higher dP/dt than GIV but without statistical difference (P>0.05). dP/dt was higher in GV than GIV but with statistically significant difference only at T30.
  
  
  CONCLUSIONS
  dP/dt was better in preconditioned hearts and was changed if using NAC in GIV. The use of NAC didn't change the effects of preconditioning on myocardial contractility in GV.
authors.affiliation: São Francisco de Assis Cardiovascular Foundation/ServCor - Belo Horizonte, MG, Brasil.
authors.forename: Denoel Marcelino de
authors.initials: DM
authors.lastname: Oliveira
authors.forename: Eros Silva
authors.initials: ES
authors.lastname: Gomes
authors.forename: Tofy
authors.initials: T
authors.lastname: Mussivand
authors.forename: Alfredo Inácio
authors.initials: AI
authors.lastname: Fiorelli
authors.forename: Otoni Moreira
authors.initials: OM
authors.lastname: Gomes
mesh_terms: D000111:Acetylcysteine / Q000008:administration & dosage*; D000704:Analysis of Variance; D000818:Animals; D003326:Coronary Circulation / Q000187:drug effects*; D016166:Free Radical Scavengers / Q000008:administration & dosage*; D006339:Heart Rate / Q000187:drug effects*; D019157:Ischemic Preconditioning, Myocardial / Q000379:methods*; D023421:Models, Animal; D009200:Myocardial Contraction / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
chemical_list: D016166:Free Radical Scavengers; D000111:Acetylcysteine