Protective mechanism of ischemic preconditioning on ischemic/reperfusion injury after pancreas transplantation in rats

Objective To investigate the protective mechanism of ischemic preconditioning on ischemic/reperfusion injury after pancreas transplantation in rats.Methods The model of diabetic SD rat was established. Twenty-four diabetic SD rats were randomly assigned to ischemic/reperfusion group (I/R group, n=6) and ischemic preconditioning group (IPC group, n=18). The rats in group IPC were averagely assigned to 3 sub-groups: group IPC_ 1 (5 min ischemic and 5 min reperfusion), IPC_ 2 (5 min ischemic and 5 min reperfusion twice) and IPC_ 3 (5 min ischemic and 5 min reperfusion thrice). Six normal SD rats whose abdomen was opened only served as control group, and they did not receive pancreas transplantation. I/R group and IPC group received pancreas transplantation. The superoxide dismutase (SOD) and myeloperoxidase (MPO) activity of grafts were monitored 2 h after reperfusion, the apoptotic cells in grafts were observed by TUNEL method, and the expression of Bcl-2 and Bax gene of the grafts was detected by Western blot.Results As compared with I/R group, the SIOD activity and the expression of Bcl-2 gene of grafts were significantly increased, while MPO activity, apoptotic index and the expression of the Bax gene in the grafts were markedly reduced in IPC group (P 0.05 ). Among the IPC groups, group IPC_ 2 showed the most significant difference (P 0.05 ).Conclusions Ischemic preconditioning can reduce apoptosis of the grafts after pancreas transplantation in rats, especially IPC_ 2 protocol. The possible mechanism might be as follows: relieving conglutination and aggregation of neutrophils, decreasing oxygen radical, up-regulating the expression of Bcl-2 gene and down-regulating the expression of Bax gene.