Landiolol does not enhance the effect of ischemic preconditioning in isolated rat hearts

Abstract

To determine the effect of landiolol on ischemic preconditioned rat hearts. Isolated perfused rat hearts were divided into 8 groups. In the control group, there was no treatment before the 30-min global ischemia. In the landiolol infused groups, landiolol (100, 300, and 500 microM) was infused without ischemic preconditioning (IPC). In other groups, hearts were pretreated with 2 episodes of 5-min global ischemia and reperfusion before the 30-min ischemia. During the preconditioning, landiolol (0, 100, 300, and 500 microM) was infused. Recoveries of coronary flow (CF) and myocardial oxygen consumption (MVO(2)) at the 120th min after global ischemia to 86 +/- 18 and 112 +/- 19% of the baseline in the IPC group was, respectively, significantly greater than that to 65 +/- 10 and 72 +/- 10% in the control group. Landiolol 300 microM also increased the CF and MVO(2) significantly (97 +/- 19 and 98 +/- 39%) compared to the control. IPC + landiolol 500 microM reduced the increase in LV end-diastolic pressure significantly compared to the control. IPC, landiolol (100, 300, and 500 microM), and IPC + landiolol (100, 300, and 500 microM) all decreased infarct sizes significantly to 23.5 +/- 15.2, 29.8 +/- 12.1, 30.2 +/- 13.3, 22.8 +/- 14.8, 21.6 +/- 7.8, 34.2 +/- 14.7 and 25.5 +/- 11.3% of the total left ventricular mass, respectively, compared to the control (53.3 +/- 12.5%), but there were no significant differences among these groups. IPC and landiolol have cardioprotective effects on ischemia-reperfusion injury in isolated rat hearts, but pretreatment with landiolol does not enhance the cardioprotective effect of IPC.