title: [Effects of remote preconditioning induced by skeletal muscle ischemia on myocardial cells apoptosis and roles of opioid receptors in pigs].
abstract: OBJECTIVE
  To investigate the effect on myocardial apoptosis and Bcl-2/Bax induced by remote preconditioning (RP) and to discuss the hypothesis from opioid receptors in pigs.
  
  
  METHODS
  Skeletal muscle ischemia was performed in pigs by occlusion of the femoral artery (FAO) for 15 min followed by a 10 min of reperfusion. Infarction of the heart was induced by 40 min of left anterior descending coronary artery (LAD) occlusion followed by 120 min reperfusion. In the RP model induced by FAO, the role of opioid receptors was investigated by using antagonist of the opioid receptors (naloxone). The signal transduction pathway of RP was investigated by using hexamethonium. Apoptosis of left ventricular samples from nonischemic and ischemic areas was detected in situ with end-labeling (TUNEL) method and measured by flow cytometry. Bcl-2 and Bax was also measured by flow cytometry.
  
  
  RESULTS
  (1) The apoptosis rate in ischemic myocardium in RP group measured by flow cytometry was lower (4.43% +/- 0.74%) compared with that in CONT group (15.4% +/- 1.15%), but Bcl-2/Bax was higher (1.36 +/- 0.09, CONT group: 0.56 +/- 0.08). (2) The protective effect could be prevented by naloxone used before RP protocol (apoptosis rate: 13.0% +/- 0.56% and Bcl-2/Bax: 0.69 +/- 0.18, P < 0.05). (3) Naloxone had no effect on apoptosis rate in CONT group. (4) Hexamethonium used before RP protocol had no effect on apoptosis rate and bcl-2/bax. Apoptotic cardiomyocytes detected in TUNEL correspond to the above.
  
  
  CONCLUSIONS
  RP induced by skeletal muscle ischemia could prevent myocardium from apoptosis, in which Bcl-2 and Bax might take part in regulation and control. Furthermore opioid receptors could take part in triggering the course and a neuronal signal transmission from the remote area to heart could be excluded.
authors.affiliation: Department of Cardiology, Second Hospital of Hebei Medical University, Shijiazhuang 050000, China.
authors.forename: Rui-Qin
authors.initials: RQ
authors.lastname: Xie
authors.forename: Wei
authors.initials: W
authors.lastname: Cui
authors.forename: Yu-Ming
authors.initials: YM
authors.lastname: Hao
authors.forename: Fan
authors.initials: F
authors.lastname: Liu
authors.forename: Bao-Hua
authors.initials: BH
authors.lastname: Li
authors.forename: Jin-Feng
authors.initials: JF
authors.lastname: Wu
authors.forename: Guo-Ying
authors.initials: GY
authors.lastname: Du
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
mesh_terms: D000818:Animals; D017209:Apoptosis; D019194:Ischemic Preconditioning / Q000379:methods*; D018482:Muscle, Skeletal / Q000098:blood supply*; D015428:Myocardial Reperfusion Injury / Q000473:pathology*; D009206:Myocardium / Q000473:pathology*; D011957:Receptors, Opioid; D013552:Swine
chemical_list: D011957:Receptors, Opioid