Effects of limb ischemic preconditioning on myocardial ischemia-reperfusion injury in a rat model of severe hemorrhagic shock and resuscitation / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the effects of limb ischemic preconditioning on myocardial ischemiareperfusion injury in a rat model of severe hemorrhagic shock and resuscitation.Methods Twenty-four male Sprague-Dawley rats,weighing 300-350 g,were randomized into 3 groups (n =8 each) using a random number table:control group (group C); severe hemorrhagic shock and resuscitation group (HSR group); limb ischemic preconditioning group (group LIP).Hemorrhagic shock and resuscitation was induced by withdrawing blood (50％ of the total blood volume) from the left common carotid artery over an interval of 1 h,and 30 min later the animals were then resuscitated by infusion of the shed blood via the jugular vein over 30 min.Limb ischemic preconditioning was induced by 4 cycles of 5 min limb ischemia followed by 5 min reperfusion at 40 min before ischemia in LIP group.Before withdrawing blood (T0),immediately after the end of withdrawing blood (T1),before infusion of the shed blood (T2),and at 0,1 and 2 h after infusion of the shed blood (T3-5),mean artery pressure (MAP) was measured,the cardiac output (CO),left ventricular ejection fraction (LVEF) and myocardial performance index (MPI) were detected using color Vivid flow imaging,and total vessel density (TVD),perfusing vessel density (PVD),proportion of perfused vessels (PPV),microvascular flow index (MFI) of sublingual microcirculation were measured using sidestream dark-field imaging.The survival rates within 72 h after hemorrhagic shock and resuscitation were recorded.Results Compared with C group,MAP,CO,LVEF,TVD,PVD,PPV and MFI were significantly decreased and MPI was increased at T1-5 in HSR group and at T1 and T2 in LIP group (P ＜ 0.01).Compared with HSR group,MAP,CO,LVEF,TVD,PVD,PPV and MFI were significantly increased and MPI was decreased at T3-5,and the survival rate within 72 h was increased in LIP group (P ＜ 0.01).Conclusion Limb ischemic preconditioning can significantly attenuate myocardial ischemiareperfusion injury induced by severe hemorrhagic shock and resuscitation in rats and is helpful for prognosis.