Investigating the effect of Na+- H+ exchanger inhibitor ? Zoniporide ? and poly(ADP-ribose) polymerase inhibitor ? 5-aminoisoquinolinone ? on isolated perfused rat heart during ischemia-reperfusion injury

SummaryIt is known that Na+- H+ Exchanger Inhibitor ? Zoniporide ? and Poly(ADP-ribose) Polymerase Inhibitor ? 5-Aminoisoquinolinone (5-AIQ) have cardioprotective effects against iscemia-reperfusion (IR) injury. The present study was performed to investigate whether the use of Zoniporide and 5-AIQ together will provide an increase in protection against IR injury. Fourty Male Sprague-Dawley rats weighing each 250-350 g were used. Rats were divided into five groups (n=8); Group 1: Sham-opereted, Group 2: IR, Group 3: (5-AIQ), Group 4: Zoniporide and Group 5: Mix (Zoniporide + 5-AIQ). Isolated rat hearts were exposed to 30 minutes of global ischemia followed by 120 minutes of reperfusion using Langendorff?s apparatus. In groups 3, 4 and 5, Zoniporide (50 nM/L) and 5-aminoisoquinolinone (7.5 ? M/L) were added into Tyrode Solution after stabilization period. In all groups hemodynamic parameters [heart rate, coronary perfusion pressure, left ventricular developed pressure (LVDP), LV(dP/dt)max and LV(dP/dt)min)] were recorded. Myocardial injury was assessed in the terms of infarct size and release of lactate dehydrogenase (LDH) enzyme. Except heart rate all parameters were found significantly different in groups 3, 4 and 5 versus IR group (p ? 0.05). When compared to Zoniporide and 5-AIQ groups, in mix group there was no significant difference determined in LDH and hemodynamic parameters (p>0.05) but myocardial infarct size estimated by volume and weight method reduced significantly [(p ? 0.05) and (p ? 0.001)]. These results show that use of Zoniporide and 5-AIQ together provides an increase in protection against IR injury especially by reducing the myocardial infarct size.Key words: Ischemia-Reperfusion Injury, Langendorff, Zoniporide, 5-Aminoisoquinolinone,Rat Heart