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Preconditioning decreases ischemia/reperfusion-induced peroxynitrite formation
1Cardiovascular Research Group, Department of Biochemistry, University of Szeged, Szeged, Hungary.
Biochemical and Biophysical Research Communications
|August 2, 2001
Summary
Preconditioning protects the heart by reducing peroxynitrite (ONOO(-)) formation during ischemia/reperfusion. This protective effect increases with repeated preconditioning, suggesting a role in ischemic adaptation.
Area of Science:
- Cardiovascular Physiology
- Biochemistry
- Oxidative Stress Research
Background:
- The role of peroxynitrite (ONOO(-)) in cardiac preconditioning remains unclear.
- Understanding ONOO(-) formation during ischemia/reperfusion is crucial for developing cardioprotective strategies.
Purpose of the Study:
- To investigate the impact of preconditioning on myocardial peroxynitrite (ONOO(-)) formation.
- To determine if ONOO(-) generation changes with repeated preconditioning insults.
Main Methods:
- Isolated rat hearts subjected to a preconditioning protocol (3x 5-min ischemia/reperfusion).
- Test ischemia/reperfusion (30-min ischemia, 15-min reperfusion) followed.
- Nitrotyrosine levels in perfusate measured as a marker for ONOO(-) formation.
Main Results:
- Preconditioning improved postischemic cardiac function compared to controls.
- Test ischemia/reperfusion-induced nitrotyrosine formation was significantly reduced by preconditioning.
- Nitrotyrosine formation increased after the first preconditioning ischemia, but decreased with subsequent periods.
Conclusions:
- Classic preconditioning inhibits ischemia/reperfusion-induced cardiac peroxynitrite (ONOO(-)) formation.
- Repeated ischemia/reperfusion periods lead to gradual attenuation of ONOO(-) generation.
- Inhibition of ONOO(-) may be a key mechanism in the heart's ischemic adaptation.