title: Protective effects of ischemic postconditioning against hypoxia-reoxygenation injury and hydrogen peroxide-induced damage in isolated rat hearts.
abstract: OBJECTIVE
  Ischemic preconditioning (PR) protects hearts from ischemia-reperfusion injury. The purpose of the present study was to examine the protective effect of PR and postconditioning (PT) against hypoxia-reoxygenation injury and H(2)O(2)-induced damage in isolated rat hearts.
  
  
  RESULTS
  Hearts from male Sprague-Dawley rats were perfused with Krebs-Henseleit solution by Langendorff methods and subjected to two protocols. In protocol A, control hearts underwent 45 min of hypoxia and 30 min of reoxygenation. Three PT cycles of 10 s of ischemia and 10 s of reperfusion after 45 min of hypoxia increased the recovery of the pressure-rate product. Three PR cycles of 3 min of ischemia and 5 min of reperfusion before hypoxia were also protective, and decreased the release of glutamic oxaloacetic transaminase. A combination of PR and PT resulted in greater protection than either alone. In protocol B, control hearts underwent perfusion with H(2)O(2) (120 muM) until the left ventricular end-diastolic pressure was elevated to 50 mmHg, and then H(2)O(2) was washed out for 30 min. Three PT cycles of 30 s of ischemia and 30 s of reperfusion before the 30 min washout increased the level of recovery of the pressure-rate product and decreased left ventricular end-diastolic pressure to baseline levels.
  
  
  CONCLUSIONS
  The results of the present study indicate that PT protects hearts from hypoxia-reoxygenation injury and H(2)O(2)-induced damage. In addition, PR combined with PT offers more effective protection than PR or PT alone.
authors.affiliation: Department of Physiology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Shanshuang
authors.initials: S
authors.lastname: Li
authors.forename: Jinrong
authors.initials: J
authors.lastname: Wu
authors.forename: Makino
authors.initials: M
authors.lastname: Watanabe
authors.forename: Chunzi
authors.initials: C
authors.lastname: Li
authors.forename: Takao
authors.initials: T
authors.lastname: Okada