Aims: To confirm whether rat islets stored at a temperature just above the freezing point using University of Wisconsin (UW) solution would remain viable for the short term.
Methodology: Rat islets were stored for 24 hours in UW solution, either at 4 degrees C or at -0.6 degrees C (just above the specific freezing point of the UW solution). After cold storage, the islets were assessed for in vitro viability by static incubation and for in vivo viability by a transplantation study. One thousand islets preserved under different conditions were injected intraportally into a streptozotocin-induced diabetic rat as an isograft. Four weeks after the transplantation, an intravenous glucose tolerance test was performed.
Results: Islets stored at -0.6 degrees C showed higher insulin secretion rates than those stored at 4 degrees C on a static challenge. The interval from transplantation to the achievement of normoglycemia was also shorter in the -0.6 degrees C group than in the 4 degrees C group. After islet transplantation, the daily nonfasting plasma glucose concentration was higher in the 4 degrees C group than in the -0.6 degrees C group. When compared with the 4 degrees C group, the -0.6 degrees C group showed lower blood glucose values during all investigational periods on an intravenous glucose tolerance test.
Conclusion: Islet preservation at -0.6 degrees C using UW solution is more advantageous for short term.