Purpose: To determine the effect of landiolol on ischemic preconditioned rat hearts.
Methods: 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.
Results: 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.
Conclusion: 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.