Polyphenol (-)-epigallocatechin gallate-induced cardioprotection may attenuate ischemia-reperfusion injury through adenosine receptor activation: a preliminary study

Abstract

BackgroundThe activation of guanine nucleotide binding protein-coupled receptors, such as adenosine receptor (ADR) and opioid receptor (OPR), protects the heart against ischemia and reperfusion injury. We hypothesized that ADR or OPR might be involved in polyphenol (-)-epigallocatechin gallate (EGCG)-induced cardioprotection.MethodsLangendorff perfused rat hearts were subjected to 30 min of regional ischemia and 2 h of reperfusion. Hearts were treated with 10 µM of EGCG, with or without the ADR or OPR antagonist at early reperfusion. Infarct size measured with 2,3,5-triphenyltetrazolium chloride staining was chosen as end-point.ResultsEGCG significantly reduced infarct volume as a percentage of ischemic volume (33.5 ± 4.1%) compared to control hearts (14.4 ± 1.1%, P 0.05 vs. EGCG) blocked the anti-infarct effect by EGCG. The infarct reducing effect of EGCG was significantly reversed by 200 nM of the A1 ADR antagonist DPCPX (25.9 ± 1.1%, P 0.05 vs. EGCG) and 100 nM of the A3 ADR antagonist MRS1334 (24.1 ± 1.8%, P > 0.05).ConclusionsThe infarct reducing effect of EGCG appears to involve activation of ADR, especially A1 and A2B ADR, but not OPR.

Keywords

• adenosine
• epigallocatechin gallate
• myocardial infarction
• reperfusion injury