The relations between interleukin-2,10 and transplantation tolerance to rat cardiac allografts induced by intrathymic inoculation

To induce tolerance to cardiac allografts by combining intrathymic inoculation with allogeneic antigen at the day of transplantation. Methods Survival time of cardiac allografts (MST), interleukin (IL-2 and IL-10) in recipient's serum, the mixed lymphocyte reaction (MLR) between donors and recipients were investigated by inducing tolerance with short-course therapy of FK506 and intrathymic inoculation. Results The MST of cardiac allografts in no treatment group, control group,classical induction group and experimental group was (6.8±1.9), (17.4±5.1), (73.8± 8.6) and (55.0±24.7) days respectively.There was no significant difference between the classical induction group and experimental group (P0.05). The proliferating response of MLR in no treatment group, classical induction group and experimental group was 198.72%,95.80% and 67.94% respectively.The proliferating responses in classical induction group and experimental group were lower than in no treatment group. The proliferating response had no significant difference between the classical induction group and experimental group (P0.05).There was no significant difference in level of IL-10 before and after-operation (52.60±10.14) ng/L vs (48.10±5.14) ng/L in no treatment group (P0.05). In the experimental group, the expression of IL-10 was down-regulated on early stage (36.10±2.30) ng/L and strongly up-regulated on medium (281.80±65.44) ng/L and late stage (80.901±12.39) ng/L after grafting.Before the grafts rejected in no treatment group, the level of IL-2 (159.80±59.19) ng/L was higher than before heart transplantation [(54.80±8.42) ng/L, P0.05].Conclusion Donor-specific tolerance was obtained by intrathymical injection of donor spleen cells on the day of transplantation as it was 21 days before transplantation. The level of IL-2 might be referable to occurrence of acute rejection and IL-10 might be relative to maintain immune tolerance.