J Korean Med Sci.  2010 Mar;25(3):380-386. 10.3346/jkms.2010.25.3.380.

Polyphenol (-)-Epigallocatechin Gallate during Ischemia Limits Infarct Size Via Mitochondrial K(ATP) Channel Activation in Isolated Rat Hearts

• Song DK
• Jang Y
• Kim JH
• Chun KJ
• Lee D
• Xu Z

• KMID: 1778032
• DOI: http://doi.org/10.3346/jkms.2010.25.3.380

Abstract

Polyphenol (-)-epigallocatechin gallate (EGCG), the most abundant catechin of green tea, appears to attenuate myocardial ischemia/reperfusion injury. We investigated the involvement of ATP-sensitive potassium (K(ATP)) channels in EGCG-induced cardioprotection. Isolated rat hearts were subjected to 30 min of regional ischemia and 2 hr of reperfusion. EGCG was perfused for 40 min, from 10 min before to the end of index ischemia. A nonselective K(ATP) channel blocker glibenclamide (GLI) and a selective mitochondrial K(ATP) (mK(ATP)) channel blocker 5-hydroxydecanoate (HD) were perfused in EGCG-treated hearts. There were no differences in coronary flow and cardiodynamics including heart rate, left ventricular developed pressure, rate-pressure product, +dP/dt(max), and -dP/dt(min) throughout the experiments among groups. EGCG-treatment significantly reduced myocardial infarction (14.5+/-2.5% in EGCG 1 micrometer and 4.0+/-1.7% in EGCG 10 micrometer, P<0.001 vs. control 27.2+/-1.4%). This anti-infarct effect was totally abrogated by 10 micrometer GLI (24.6+/-1.5%, P<0.001 vs. EGCG). Similarly, 100 micrometer HD also aborted the anti-infarct effect of EGCG (24.1+/-1.2%, P<0.001 vs. EGCG ). These data support a role for the K(ATP) channels in EGCG-induced cardioprotection. The mK(ATP) channels play a crucial role in the cardioprotection by EGCG.

Keyword

Epigallocatechin Gallate; KATP Channels; Myocardial Infarction; Myocardial Ischemia; Myocardial Reperfusion Injury

MeSH Terms

Animals
Anti-Arrhythmia Agents/pharmacology
Antioxidants/*pharmacology
Catechin/*analogs & derivatives/pharmacology
Decanoic Acids/pharmacology
Glyburide/pharmacology
Heart/*drug effects/physiology/physiopathology
Hemodynamics
Humans
Hydroxy Acids/pharmacology
KATP Channels/*metabolism
Male
Mitochondria, Heart/*drug effects/metabolism
Myocardial Infarction/*pathology
Myocardial Ischemia/*pathology
Potassium Channel Blockers/pharmacology
Rats
Rats, Wistar
Anti-Arrhythmia Agents
Antioxidants
Decanoic Acids
Hydroxy Acids
KATP Channels
Potassium Channel Blockers
Glyburide
Catechin