Effects of preconditioning with isoflurane and propofol on myocardial ischemia-reperfusion injury in rats

Objective To evaluate the effects of preconditioning with isoflurane and propofol on myocardial ischemia-reperfusion(I/R)injury in rots.Methods Thirty-six male Wistar rats weighing 250-300 g were randomly divided into 4 groups(n=9 each)： group Ⅰ I/R; group Ⅱ isoflurane preconditioning(group Ⅰ);group Ⅲ propofol preconditioning(group P)and group Ⅳ preconditioning with isoflurane and propofol(group I+P).The animals were anesthetized with intraperitoneal urethane.The trachea was intubated.The animals were mechanically ventilated.In group Ⅱ and Ⅳ the animals received 2 episodes of 10 min 1.6% isoflurane inhalation at 5 min intervals before I/R; in group Ⅲ and Ⅳ the animals received 2 episodes of 10 rain iv propefol infusion at 37.5 mg·kg~(-1)·h~(-1) at 5 min intervals before I/R.Preconditioning with isoflurane and propefol was performed simultaneously in group I+P(Ⅳ).Myocardial I/R was produced by 60 min occlusion of left anterior descending coronary artery followed by 120 min reperfusion.The animals were sacrificed at the end of 120 min reperfusion and the hearts were removed for microscopic examination with transmission electron microscope，detection of myocyte apoptosis by TUNEL staining and determination of mitochondrial ROS level by fluorescence staining.Results Cardiomyocyte apoptosis was detected by transmission electron microscopy.Apoptosis index and mitochondrial ROS level were significantly lower in group I，group P and group I+P than in group I/R，but no difference was found among the 3 preconditioning groups.Conclusion The protection provided by preconditioning with isoflurane or propofol or isoflurane+propofol against myocardial I/R is comparable. Key words: Isoflurane; Propofol; Ischemic preconditioning; Myocardial reperfusion injury