Abstract:

BACKGROUND: Ischemic preconditioning (IPC) can induce endogenous protection mechanism, which effectively prevent ischemia/reperfusion injury following organ transplantation. Cold and warm ischemia may induce ischemia/reperfusion injury of pancreas transplantation, and apoptosis of pancreatic acinar cells is one of the important reasons of pancreas graft functional defect after transplantation. Mitochondrial DNA has repair system, and its balance with mitochondrial DNA injury influences disease occurrence and outcome.
OBJECTIVE: To observe the effect of IPC on apoptosis of transplanted pancreatic acinar cells, and the possible role of reactive oxygen (ROS) and mitochondrial DNA repair enzyme.
METHODS: A total of 50 health, male, Sprague-Dawley rats were randomly divided into three groups: sham operated (n = 10), donors (n = 20) and recipients (n = 20). The recipients were randomly divided into ischemia/reperfusion group (IR, n = 10) and IPC group (n = 10). The sham operated group was subjected to abdominal open and close operation. IR group and IPC group received establishment of diabetic model by streptozotocin injection. IR rats received whole pancreatic-duodenal transplantation alone. IPC rats received whole pancreatic-duodenal transplantation exposed ischemic preconditioning with 5 minutes ischemia and 5 minutes reperfusion twice. All grafts were keep with warm ischemia time 15 minutes and cold ischemia (in 4 ℃ UW preservation solution) time 180 minutes. Twelve hours after reperfusion, serum amylase, blood glucose, Caspase-3, -9 activity were detected. Pancreatic acinar cell apoptosis was measured by flow cytometry. Mitochondrial cross-membrane potential (△Ψ) was measured by monitoring the fluorescence spectrum of rhodamine 123. Mitochondrial H2O2 generation was determined using dichlorofluorescein as a probe. 8-oxodG in mitochondrial DNA (mtDNA) was measured with HPLC system.  Release of cytochrome C, phosphorylation of Akt and mitochondrial OGG1 protein expression were determined by Western-blotting.
RESULTS AND CONCLUSION: The ischemia preconditioning can relieve the pancreatic acinar cell apoptosis in pancreas graft and relieve IR injury by decreasing mitochondrial oxidative stress, mtDNA injury, and increasing phosphorylation of Akt and mitochondrial OGG1 expression.