Oral pretreatment with a green tea polyphenol for cardioprotection against ischemia-reperfusion injury in an isolated rat heart model.

OBJECTIVE: Ischemia-reperfusion injury is among the most serious problems in cardiac surgery. Epigallocatechin-3-gallate, a major polyphenolic component of green tea, is thought to be cardioprotective through its antioxidant activities. We investigated cardioprotective effects of oral epigallocatechin-3-gallate pretreatment against ischemia-reperfusion injury in isolated rat hearts and considered possible underlying mechanisms.
METHODS: Rats were given epigallocatechin-3-gallate solution orally at 0.1, 1, or 10 mmol/L (n=12 per group) for 2 weeks; controls (n=12) received tap water alone for 2 weeks. Subsequently, Langendorff-perfused hearts were subjected to global ischemia for 30 minutes, followed by 60 minutes of reperfusion.
RESULTS: Recoveries at 60 minutes after reperfusion of left ventricular developed pressure and maximum positive and minimum negative first derivatives of left ventricular pressure were significantly higher in 1-mmol/L group than in 0.1-mmol/L (P<.0001), 10-mmol/L (P<.05), and control (P<.0001) groups. Oxidative stress after reperfusion, as reflected by 8-hydroxy-2'-deoxyguanosine index, was lower in 1-mmol/L group than in control (P<.01) and 0.1-mmol/L (P<.05) groups. Western blot analysis after reperfusion showed p38 activation and active caspase-3 expression to be lower in 1-mmol/L group than in control group (P<.05).
CONCLUSIONS: Oral pretreatment with epigallocatechin-3-gallate preserved cardiac function after ischemia-reperfusion, an effect that may involve its antioxidative, antiapoptotic properties, although a high dose did not lead to dramatic improvement in cardiac function. Oral epigallocatechin-3-gallate pretreatment may be a novel and simple cardioprotective method for preventing perioperative cardiac dysfunction in cardiac surgery. Copyright Â