Effect of Ischemic Preconditioning and Propofol on Myocardial Protection in the Globally Ischemic-reperfused Isolated Rat Heart

Abstract

Background: Although ischemic preconditioning (IPC) or propofol is generally known to confer the cardioprotective effect on ischemic-reperfused hearts, especially in patients subjected to operation such as cardiopulmonary bypass and heart transplantation, the exact effects of IPC and propofol are still controversial. Furthermore, the interaction between IPC- and propofol-induced cardioprotective effects has not been studied yet. The aims of this study are to examine 1) whether IPC and propofol demonstrates the cardioprotective effect against ischemic-reperfusion injury in the isolated rat hearts, and if so, 2) whether the combination of IPC and propofol shows the additive effects. Methods: Isolated rat hearts were subjected to 30 min global ischemia followed by 60 min of reperfusion. Four groups of hearts (n = 7 per group) were studied. Group control (no intervention); group IPC, two 2-min total coronary occlusions (ischemic preconditioning) interspersed with 5 min and 6 min of normal perfusion before global ischemia; group propofol, propofol 2/ml (11.1M) administered before global ischemia and during reperfusion; group propofol/IPC, propofol 2/ml administered before IPC and during reperfusion. Left ventricular developed pressure (LVDP), left ventricular end-diastolic pressure (LVEDP), + and - were recorded and creatinine kinase (CK) in coronary effluent perfusate and coronary flow also were measured. Results: There were significant differences in recovery of postischemic systolic function between control and IPC, propofol and propofol/IPC as assessed by LVDP, expressed as a percentage of preischemic value (22.2 8.4 vs 59.4 6.8, 69.4 7.9 and 66.0 7.1%, respectively; P T 2.2 and 11.3 6.1 vs 56 6.0 or, 25.2 7.6 mmHg, respectively; P 54.7 vs 602.3 / 225.1%, P ｷ 4.0 vs 39.2 5.2%, P