title: [Effects of BNP preconditioning on myocardial cell apoptosis and expressions of bcl-2 and Bax during myocardial ischemia-reperfusion injury in rats].
abstract: OBJECTIVE
  To study the effects of B-type natriuretic peptide (BNP) preconditioning on the apoptosis and expressions of Bcl-2 and Bax in rat cardiomyocytes during myocardial ischemia-reperfusion.
  
  
  METHODS
  Twenty-one male Sprague-Dawley rats weighing (250 ± 50) g were randomly divided into 3 groups of sham operation (SHAM), ischemia-reperfusion (I/R) and B-type natriuretic peptide (BNP). A rat model of in vivo myocardial ischemia-reperfusion injury was established by ligating the left anterior descending coronary artery for 35 minutes and then reperfusing for 240 minutes. The apoptosis of myocardial cell was determined by terminal deoxynucleotidyl transferase mediated dUTP-biotin nick end-labeling (TUNEL) method. Real-time polymerase chain reaction and Western blot were used to detect the expression changes of Bcl-2 and Bax in rat ischemia myocardium.
  
  
  RESULTS
  The apoptotic indices of SHAM, BNP and I/R groups were 5.4% ± 4.2%, 22.5% ± 9.5% and 45.2% ± 13.0% respectively (P < 0.05). The Bcl-2 protein expression of SHAM, BNP and I/R groups were 0.87 ± 0.09, 0.70 ± 0.07 and 0.38 ± 0.09 respectively (P < 0.05). The Bax protein expression of SHAM, BNP and I/R groups were 0.08 ± 0.04, 0.39 ± 0.09 and 0.71 ± 0.18 respectively (P < 0.01). The Bcl-2/Bax mRNA ratio of SHAN, BNP and I/R groups were 0.763 ± 0.154, 0.099 ± 0.025 and 0.022 ± 0.024 respectively (P < 0.05).
  
  
  CONCLUSIONS
  The BNP preconditioning can decrease the myocardial apoptosis induced by ischemia-reperfusion injury. The mechanisms may be associated with an elevated expression of Bcl-2, an increased ratio of Bcl-2/Bax and a lowered expression of Bax.
authors.affiliation: Guangdong General Hospital, Guangdong Academy of Medical Sciences, Emergency and Critical Care Department, Guangdong Provincial Cardiovascular Institute, Research Center of Medical Sciences, Guangzhou 510080, China.
authors.forename: Yu-Jun
authors.initials: YJ
authors.lastname: Deng
authors.forename: Ning
authors.initials: N
authors.lastname: Tan
authors.forename: Hong-Ke
authors.initials: HK
authors.lastname: Zeng
authors.forename: Yong-Heng
authors.initials: YH
authors.lastname: Fu
authors.forename: Xiao-Li
authors.initials: XL
authors.lastname: Dong
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D019157:Ischemic Preconditioning, Myocardial / Q000379:methods; D008297:Male; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism*; D020097:Natriuretic Peptide, Brain / Q000494:pharmacology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury; D051028:bcl-2-Associated X Protein / Q000378:metabolism*
chemical_list: C494828:Bax protein, rat; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D020097:Natriuretic Peptide, Brain