Effects of sevoflurane preconditioning and postconditioning on rat myocardial stunning in ischemic reperfusion injury

Abstract

Ischemic preconditioning and postconditioning distinctly attenuate ventricular arrhythmia after ischemia without affecting the severity of myocardial stunning. Therefore, we report the effects of sevoflurane preconditioning and postconditioning on stunned myocardium in isolated rat hearts. Isolated rat hearts were underwent 20 min of global ischemia and 40 min of reperfusion. After an equilibration period (20 min), the hearts in the preconditioning group were exposed to sevoflurane for 5 min and next washout for 5 min before ischemia. Hearts in the sevoflurane postconditioning group underwent equilibration and ischemia, followed immediately by sevoflurane exposure for the first 5 min of reperfusion. The control group received no treatment before and after ischemia. Left ventricular pressure, heart rate, coronary flow, electrocardiogram, and tissue histology were measured as variables of ventricular function and cellular injury, respectively. There was no significant difference in the duration of reperfusion ventricular arrhythmias between control and sevoflurane preconditioning group (P=0.195). The duration of reperfusion ventricular arrhythmias in the sevoflurane postconditioning group was significantly shorter than that in the other two groups (P<0.05). +/-(dP/dt)(max) in the sevoflurane preconditioning group at 5, 10, 15, 20, and 30 min after reperfusion was significantly higher than that in the control group (P<0.05), and there were no significant differences at 40 min after reperfusion among the three groups (P>0.05). As expected, for a 20-min general ischemia, infarct size in heart slices determined by 2,3,5-triphenyltetrazolium chloride staining among the groups was not obvious. Sevoflurane postconditioning reduces reperfusion arrhythmias without affecting the severity of myocardial stunning. In contrast, sevoflurane preconditioning has no beneficial effects on reperfusion arrhythmias, but it is in favor of improving ventricular function and recovering myocardial stunning. Sevoflurane preconditioning and postconditioning may be useful for correcting the stunned myocardium.

Fig. 1

Experimental protocols used in this study CON: control group; SPR: sevoflurane preconditioning group; SPO: sevoflurane postconditioning group

Fig. 2

Duration of reperfusion arrhythmias Data are mean±SD, n=8 in each groups; ^* P<0.05 vs. CON; ^# P<0.05 vs. SPR. CON: control group; SPR: sevoflurane preconditioning group; SPO: sevoflurane postconditioning group

Fig. 3

Maximal rise/fall rate of left ventricular pressure [+(dP/dt)_max] Data are mean±SD, n=8 in each groups; ^* P<0.05 vs. CON; ^# P<0.05 vs. SPR. CON: control group; SPR: sevoflurane preconditioning group; SPO: sevoflurane postconditioning group

Fig. 4

Minimal rise/fall rate of left ventricular pressure [−(dP/dt)_min] Data are mean±SD, n=8 in each groups; ^* P<0.05 vs. CON; ^# P<0.05 vs. SPR. CON: control group; SPR: sevoflurane preconditioning group; SPO: sevoflurane postconditioning group

Fig. 5

Left ventricular developed pressure (LVDP) Data are mean±SD, n=8 in each groups; ^* P<0.05 vs. CON; ^# P<0.05 vs. SPR. CON: control group; SPR: sevoflurane preconditioning group; SPO: sevoflurane postconditioning group

Fig. 6

Coronary flow (CF) Data are mean±SD, n=8 in each groups; ^* P<0.05 vs. CON; ^# P<0.05 vs. SPR. CON: control group; SPR: sevoflurane preconditioning group; SPO: sevoflurane postconditioning group

Fig. 7

Heart rate (HR) Data are mean±SD, n=8 in each groups; ^* P<0.05 vs. CON; ^# P<0.05 vs. SPR. CON: control group; SPR: sevoflurane preconditioning group; SPO: sevoflurane postconditioning group