Oxidative injury of isolated cardiomyocytes: dependence on free radical species.
The contribution of lipid peroxidation to myocardial injury by free radicals (FR) is still unclear. Consequently, we examined the functional damages inflicted on cultured rat cardiomyocytes (CM) during FR stress provoked by the xanthine/xanthine oxidase system (X/XO) or by a hydroperoxidized fatty acid ((9 Z, 11 E, 13 (S), 15 Z)-13-hydroperoxyocta-decatrienoic acid; 13-HpOTrE), in order to simulate in vitro the initial phase and the propagation phase of the FR attack, respectively. Transmembrane potentials were recorded with glass microelectrodes and contractions were monitored photometrically. The EPR spectroscopy showed that X/XO produced superoxide and hydroxyl radicals during 10 min. The X/XO system altered sharply and irreversibly the spontaneous electrical and mechanical activities of the CM. However, the gas chromatographic analysis showed that these drastic functional damages were associated with comparatively moderate membrane PUFA degradation. Moreover, the EPR analysis did not reveal the production of lipid-derived FR. 13-HpOTrE induced a moderate and reversible decrease in electrical parameters, with no change in CM contractions. These results indicate that the functional consequences of FR attack are dependent on the radical species present and do not support the idea that the membrane lipid breakdown is a major factor of myocardial oxidant dysfunction.
Durot
I
I
Laboratory of Cardiovascular Physiopathology and Pharmacology, Faculties of Medicine and Pharmacy, 21079, Dijon, France.
Maupoil
V
V
Ponsard
B
B
Cordelet
C
C
Vergely-Vandriesse
C
C
Rochette
L
L
Athias
P
P
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002478:Cells, Cultured; D004578:Electron Spin Resonance Spectroscopy; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism; D005609:Free Radicals / Q000378:metabolism; D006321:Heart / Q000187:drug effects; D066298:In Vitro Techniques; D015227:Lipid Peroxidation / Q000187:drug effects; D009200:Myocardial Contraction / Q000187:drug effects; D015428:Myocardial Reperfusion Injury / Q000209:etiology / Q000378:metabolism; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D018384:Oxidative Stress; D051381:Rats; D019820:Xanthine / Q000378:metabolism / Q000494:pharmacology; D014969:Xanthine Oxidase / Q000378:metabolism / Q000494:pharmacology
D005227:Fatty Acids; D005609:Free Radicals; D019820:Xanthine; D014969:Xanthine Oxidase