OBJECTIVETo identify associated proteins involved in the molecular response of ischemic preconditioning (IPC) against intestinal ischemia/reperfusion (II/R) in the intestinal mucosa of rats.

METHODSSixteen SD rats were randomly divided into II/R and IPC groups. II/R injury in rats was produced by clamping superior mesenteric artery for 60 min followed by 60 min reperfusion. IPC was elicited by 20 min ischemia and 5 min reperfusion before index ischemia. The intestinal mucosa was scratched immediately after 60 min of reperfusion and total proteins were separated by immobilized pH gradient (IPG) based on two-dimensional gel electrophoresis (2-DE). The differentially expressed proteins were analyzed using Image Master 2D Elite 5.0 image analysis software and identified by MALDI-TOF-MS. The biological information of these proteins was searched in the database of these peptide mass finger-printing (PMF). Western blotting and RT-PCR were used to validate the differentially expressed proteins.

RESULTSImage analysis revealed that averages of 1404+/-20 and 1338+/-20 were detected in II/R and IPC groups. A total of 10 spots yielded good spectra, and 8 spots matched with known proteins after database searching. These proteins were mainly involved in anti-oxidation, inhibiting apoptosis and energy metabolism. Western blot confirmed up-regulation of aldehyde dehydrogenase and RT-PCR confirmed up-regulation of aldose reductase in IPC group.

CONCLUSIONThe clues provided by comparative proteome strategy will shed light on molecular mechanisms of IPC against II/R injury.