301. Preconditioning with hydrogen peroxide (H2O2) or ischemia in H2O2-induced cardiac dysfunction.
- Author
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Valen G, Starkopf J, Takeshima S, Kullisaar T, Vihalemm T, Kengsepp AT, Löwbeer C, Vaage J, and Zilmer M
- Subjects
- Animals, Antioxidants analysis, Blood Pressure, Coronary Circulation, Dose-Response Relationship, Drug, Heart physiopathology, Heart Rate, In Vitro Techniques, Lipid Peroxidation, Male, Myocardial Ischemia drug therapy, Myocardium metabolism, Perfusion, Rats, Rats, Sprague-Dawley, Troponin T analysis, Troponin T metabolism, Ventricular Function, Left, Antioxidants metabolism, Hydrogen Peroxide pharmacology, Ischemic Preconditioning, Myocardial methods, Myocardial Ischemia metabolism, Reactive Oxygen Species metabolism
- Abstract
The possible cardioprotective effects of preconditioning by ischaemia (IPC) or a low dose of H2O2 (HPC) prior to a high dose of H2O2 was investigated. Langendorff-perfused rat hearts (n = 10 in each group) were subjected to 10 min of 140 micromol/L H2O2 and 30 min recovery after either (1) control perfusion, (2) 20 micromol/L H2O2 for 10 min, recovery 10 min, or (3) 2 x 2 min global ischaemia and 5 min reperfusion. 140 micromol/L H2O2 increased left ventricular end-diastolic pressure from 0 to 68+/-8 mmHg in controls (mean+/-SEM), which was attenuated by IPC (46+/-9 mmHg, p<0.001) and HPC (18+/-4 mmHg, p < 0.001 compared to controls, p < 0.01 compared to IPC). HPC, but not IPC, improved coronary flow (p < 0.02) and left ventricular developed pressure (p < 0.001) during recovery. Troponin T release was similar in all groups. Tissue thiobarbituric acid reactive substances, antioxidant capacity, catalase, and glutathione peroxidase were not influenced by 140 micromol/L H2O2. H2O2 decreased the level of tissue glutathione. This reduction was augmented by HPC (p <0.02) and attenuated by IPC (p < 0.02). H2O2 increased superoxide dismutase (p < 0.04). The increase was attenuated by IPC (p < 0.05), but not influenced by HPC. HPC efficiently protected cardiac function in H2O2-induced cardiac injury, while IPC had only a small protective effect. The functional protection cannot be explained by reduction of irreversible injury, attenuation of lipid peroxidation, or modification of tissue antioxidant parameters. more...
- Published
- 1998
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