Comparison of Protective Effects of Catechin Applied in Vitro and in Vivo on Ischemia-Reperfusion Injury in the Isolated Rat Hearts

Aim. To determine and compare overall cardiac effects of flavonoid catechin, applied in vitro or in vivo, on ischemia-reperfusion injury in isolated rat hearts. Methods. After perfusing hearts at 70 mm Hg, coronary perfusion was interrupted for 30 minutes and then reestablished. There were four experimental groups (n=10 each): (I) 100 m ; ; M/L of catechin added to the perfusate 10 minutes before, during and 10 minutes after ischemia ; (II) in vivo pretreatment with catechin (250 mg/kg b.w.) applied intragastrically for 10 days or (III) as a single dose 1 hour before sacrifice ; and (IV) control. An additional group of 10 hearts served as untreated, nonischemic time control. The variables included heart rate, atrioventricular conduction time, cardiac rhythm, isovolumetric left ventricular pressure, coronary flow and responsiveness, oxygen consumption, relative cardiac efficiency, lactate dehydrogenase release, and myocardial lipid peroxidation. Results. Catechin added to the perfusate increased the coronary flow and ratio of oxygen delivery to myocardial oxygen consumption, before ischemia and during reperfusion. Following 30 minutes of reperfusion, isovolumetric left ventricular developed pressure recovered to 42p ; ; ; ; ; ; 3%, 63p ; ; ; ; ; ; 3%, 71p ; ; ; ; ; ; 2%, and 55p ; ; ; ; ; ; 3% of the initial control values for control, catechin 1 hour, catechin for 10 days and catechin in vitro group, respectively. Cardiac efficiency and coronary responsiveness were also best preserved in the group receiving catechin for 10 days. Conclusion. Application of catechin both in vitro, and short and long term in vivo, resulted in cardioprotection against ischemia-reperfusion injury, but long term pretreatment provided more favorable effects. Directly applied, catechin acted as a vasodilator.