GENERATION OF NITRIC-OXIDE AS A REJECTION MARKER IN RAT PANCREAS TRANSPLANTATION

In clinical pancreas transplantation, no reliable marker for the early diagnosis of acute rejection has been reported, This is one reason wh y the graft survival rate of pancreas transplantation alone is much lo wer than that of other organs, such as hearts, livers, and kidneys, We designed an experiment to investigate acute rejection of pancreas all ografts in hyperglycemic rats by measurement of blood glucose levels a nd nitric oxide (NO) products (nitrite plus nitrate, and nitrosyl hemo globin), As recipients, Lewis rats were rendered hyperglycemic by intr avenous injection of streptozotocin before transplantation. F344 rats were used as donors of pancreas allografts, Lewis rats were also used as donors of syngeneic pancreas grafts, After transplantation, the blo od glucose level returned to a normal level and rejection was defined as the recurrence of hyperglycemia. The mean survival time of pancreas allografts was 14+/-0.7 days. The plasma level of nitrite plus nitrat e in allografted rats peaked on postoperative day 7, Electron spin res onance spectra of NO bound to hemoglobin were detected in the blood fr om allografted rats with a peak on postoperative day 7, whereas NO bou nd to hemoglobin was not detected in the blood from recipients of syng eneic grafts at any sampling time, The results show that NO was synthe sized in the earlier period than the elevation of the blood glucose le vel during rejection after pancreas transplantation in rats.