Cardiac transplantation tolerance induced by perioperative injection of spleen cells through portal vein in allogeneic rats

Objective:To induce cardiac transplantation tolerance in rat by perioperative injection of spleen cells into portal vein,and to study the mechanism concerning transplantation tolerance.Methods:The heart transplantation operation was carried out and allogeneic spleen cells in an amount of 3×10 8 were injected via portal vein during the operation.Cyclophosphamide was injected intraperitoneally in a dose of 80 mg/kg 2 days later.The survival time was observed and monitored.The tolerant mechanism was investigated by mixed lymphocyte reaction (MLR),delayedtype hypersensitivity (DTH),interleukin2 (IL2) reverse test and detection of microchimerism.Results:The cardiac allograft survival was significantly prolonged;MLR and DTH demonstrated that immune response of recipient rats was inhibited,and it was donorspecific.The IL2 reverse test and detection of microchimerism showed that the tolerance mechanism involved anergy,and was related to formation of microchimerism.Conclusions:The tolerance induction protocol significantly prolonged cardiac allograft survival in rat,and it appears to be worthy of a clinical trial.This tolerance involved multiple mechanisms.