Prolonged Cold Ischemic Time Results in Increased Acute Rejection in a Rat Allotransplantation Model

BackgroundThe cold ischemic time may be more prolonged for facial tissue allografts than for organ allografts. Previous researches have shown that prolonged ischemia resulted in increased signs of rejection in a rat groin allotransplantation model; however, the relationship between cold ischemia and alloantigen-induced rejection was unclear.Materials and MethodsVascularized groin flaps were transplanted from BN to Lewis rats after 0, 6, 12, 18, or 24 h of storage at 4°C, and the allografts in each group were evaluated daily. Biopsy samples taken from the allo-0 h and allo-24 h groups on postoperative d 2–8 were graded for signs of acute rejection. Biopsy samples taken from the allo-0 h and allo-24 h groups on postoperative d 5 were stained for chemokine receptor CXCR3.ResultsWhen the cold ischemia time was greater than 18 h, the survival time of the grafts was significantly shorter (6.2 ± 1.3 d) than that of the grafts that did not undergo cold ischemia (9.0 ± 1.2 d). Histologicalvaluation showed acceleration of activated lymphocyte infiltration in the allo-24 h group (2.2 ± 0.4 d) compared with the allo-0 h group (4.8 ± 0.4 d). Furthermore, the proportion of CXCR3-positive cells in the allo-24 h group (49.7% ± 6.0%) was significantly higher than that in the allo-0 h group (22.9% ± 3.4%) on d 5 after transplantation.ConclusionsProlonged ischemia has a deleterious effect on allograft survival, and the chemokine receptor CXCR3 may play a role in this process.