Prolonged rat pancreas preservation using a solution with the combination of histidine and lactobionate

A newly formulated solution consisting of lactobionate with or without histidine was tested in the preservation of the rat pancreas. Adult male Lewis rats weighing 120-250 g were used as donors and recipients. Fifty-four rat pancreas transplants were performed to investigate the effectiveness of this test solution and to compare it with the standard University of Wisconsin (UW) solution. The final osmolarity of the new test solution was 290-320 mosmol/l. This solution had a higher sodium content and lower potassium content (Na: 110 mEq/l, K: 50 mEq/l). Adenosine, insulin, hydroxyethyl starch and dexamethasone, which are components of the UW solution, were not present in this test solution. Histidine was used as a buffer. Rat pancreases were stored at 4 degrees C in either standard UW solution, or high-Na+-histidine solution, or high-Na+-lactobionate solution for 48 h and 72 h prior to heterotopic transplantation into rats with streptozotocin-induced diabetes mellitus. Functional success rates for rats receiving pancreases that had been preserved in high-Na+-histidine and in high-Na+-lactobionate solutions at 4 degrees C were 100% (5/5) and 100% (7/7) after 48 h preservation, and 50% (4/8) and 14% (1/7) after 72 h preservation, respectively. By contrast, standard UW solution gave only a 44% (4/9) success rate after 48 h preservation and a 0% (0/8) success rate after 72 h preservation. These results demonstrated that the high-Na+-histidine solution was superior to standard UW solution for rat pancreas preservation. This was probably due to the buffer, histidine, which prevented the acidosis of ischemic tissue during the period of preservation.