Pyruvate improves myocardial tolerance to reperfusion injury by acting as an antioxidant: a chemiluminescence study.
BACKGROUND
There is indirect evidence that pyruvate improves myocardial tolerance to ischemia by scavenging oxygen radicals during reperfusion. The objectives of this study were to evaluate (1) lucigenin-enhanced chemiluminescence (LEC) as a method to measure oxygen radical (OR) production in vitro and in vivo and (2) the antioxidant effect of pyruvate during myocardial reperfusion.


METHODS
LEC was measured in vitro by adding to lucigenin (1) increasing concentrations of H2O2, (2) H2O2 and different concentrations of catalase, and (3) H2O2 plus pyruvate. Isolated rat hearts perfused with Krebs Henseleit-Lucigenin inside a chemiluminescence chamber were subjected to equilibration, ischemia, and reperfusion without (control) or with pyruvate. Developed pressure, contractility, compliance, and chemiluminescence were recorded.


RESULTS
In vitro, LEC directly correlated with H2O2 concentrations (r2 = 0.997) and decreased in the presence of catalase or pyruvate. During myocardial reperfusion there was a surge of chemiluminescence that peaked at 4 minutes. Pyruvate decreased the initial reperfusion peak (9.8 +/- 0.3 x 10(3) cpm in pyruvate group vs 12.4 +/- 0.9 x 10(3) cpm in control; p < 0.05) and the total amount of chemiluminescence generated during reperfusion (65.7 +/- 12 x 10(3) in pyruvate group vs 117.1 +/- 8.2 x 10(3) counts in control; p < 0.05). Pyruvate improved recovery of function after ischemia reperfusion.


CONCLUSIONS
LEC is a sensitive indicator of H2O2 concentrations and can evaluate the effect of antioxidants in vitro. It is a continuous, sensitive, and direct measurement of OR production in vivo. LEC is ideal for the evaluation of antioxidant interventions and provides direct evidence that pyruvate acts as an antioxidant while improving myocardial function during reperfusion.
Crestanello
J A
JA
Department of Cardiothoracic Surgery, Allegheny University of the Health Sciences, Philadelphia, Pa. 19129, USA.
Lingle
D M
DM
Millili
J
J
Whitman
G J
GJ
D000166:Acridines; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D002374:Catalase / Q000494:pharmacology; D016166:Free Radical Scavengers / Q000494:pharmacology; D006321:Heart / Q000187:drug effects* / Q000503:physiopathology; D006861:Hydrogen Peroxide / Q000494:pharmacology; D066298:In Vitro Techniques; D008163:Luminescent Measurements; D015428:Myocardial Reperfusion Injury / Q000503:physiopathology*; D019289:Pyruvic Acid / Q000494:pharmacology*; D051381:Rats
D000166:Acridines; D000975:Antioxidants; D016166:Free Radical Scavengers; C033472:10,10'-dimethyl-9,9'-biacridinium; D019289:Pyruvic Acid; D006861:Hydrogen Peroxide; D002374:Catalase