ABSTRACT
The present study aimed to investigate the change of cytochrome c in postconditioning-attenuated ischemia-reperfusion (I/R)-induced mucosal apoptosis in rat intestine compared with ischemic preconditioning (IPC). Using rat model of intestine I/R injury, male Sprague-Dawley rats weighing 220-250 g were divided into 4 groups which were Sham operation group, I/R group, IPC group and ischemic postconditioning (IPOST) group. In these groups, I/R procedure was performed by the occlusion of the superior mesenteric artery (SMA) for 45 min followed by reperfusion for 1 h. In Sham group, there was no intervention. In IPC group, SMA was occluded for 5 min and reperfused for 5 min, for two cycles, before the prolonged occlusion. In IPOST group, three cycles of 30-s reperfusion and 30-s reocclusion were preceded at the start of reperfusion. After the reperfusion, the small intestines were sampled for experimental detection. Intestinal mucosal mitochondrial membrane potential was detected by confocal laser scanning microscopy. Expressions of cytochrome c and caspase-3 proteins were detected using Western-blot method. The apoptosis of intestinal mucosal cells was determined with agarose gel electrophoresis and deoxynucleotidyl transferase mediated dUTP-biotin nick-end labeling (TUNEL) technique. Compared with I/R group, the mitochondrial membrane potentials and the expressions of cytochrome c protein were significantly increased, while the expressions of caspase-3 and the apoptotic rates were decreased in IPOST and IPC groups (P<0.05). There were no significant differences between IPOST and IPC groups (P>0.05). These data provide substantial evidence that IPOST attenuates I/R-induced mucosal apoptosis by reducing the release of cytochrome c from mitochondria in the rat small intestine.