Apoptosis is Caused by Prolonged Organ Preservation and Blocked by Apoptosis Inhibitor in Experimental Rat Pancreatic Grafts

Unlabelled: Apoptosis is a major mode of cell death after ischemia/reperfusion injury in several organs. The aims of this study were to evaluate apoptosis induction after different conditions of pancreas preservation and to investigate the impact of a caspase inhibitor on apoptosis induction in pancreatic grafts.

Methods: Inbred male Lewis rats served as donors and recipients. Apoptosis was detected using an in situ cell death detection kit and an apoptotic DNA ladder kit (Roche, Germany). An apoptotic index (AI) was defined as the number of apoptotic cells per field (400x) under a light microscope. The five groups included: group 1 (n = 5), normal pancreata; group 2 (n = 7), pancreata stored in University of Wisconsin (UW) solution (4 degrees C) for 6 hours (hr); group 3 (n = 7), pancreata preserved in UW solution (4 degrees C) for 18 hr; group 4 (n = 7), pancreata preserved in 0.9% saline (4 degrees C) for 6 hours; and group 5 (n = 5), pancreata preserved in 0.9% saline (4 degrees C) for 6 hours with Z-Asp-2,6-dichlorobenzoyloxymethylketone (caspase inhibitor) treatment. The pancreatic grafts in all experimental groups underwent a 2-hr period of reperfusion after transplantation.

Results: The results in this study showed that the AI was not significantly increased among pancreatic grafts in group 2 compared to group 1 (P >.05). However, AI in group 3 was significantly higher than that in group 2 (P <.05). The highest AI was observed in group 4. Interestingly, AI in group 5 was significantly lower than that in group 4 (P <.01), and not significantly different from group 1 (P >.05). Apoptotic DNA ladders were detected in the pancreatic grafts in group 2, 3, and 4, but not in group 1 and 5.

Conclusions: Prolonged preservation of pancreata in cold UW solution induces a dramatic increase in apoptotic cell death among the pancreatic grafts following Tx. This observation may well be an important mechanism of graft damage. A caspase inhibitor might be useful to inhibit apoptosis induction in pancreatic grafts.