The effect of transfusion of donor apoptotic cells on CD4~+ CD25~+ T lymphocytes in diabetic rat undergoing islets transplantation

Objective To investigate the influence of transfusion of donor apoptotic cells on the the ratio of CD4~+ CD25~+ to CD4~+ T lymphocytes in the rat immune tolerance to allogenie islets transplantation. Methods Recipient SD rats were rendered diabetic by a single intraperitoneal injection of streptozotocin (STZ). Apoptotic splenocytes of donor Wistar rat were induced by X-irradiation from electron linear accelerator. Then, the donor apoptotie splenocytes were injected into the recipient SD rats. Seven days later, diabetic SD rats received islets transplantation under their renal capsule. The blood glucose and allograft survival time were detected to reflect the function of the islets grafts. The ratio of CD4~+ T to CD4~+ CD25~+T lymphocytes was detected by flow cytometry. Results The pre-infused donor apoptotic splenocytes significantly prolonged allograft survival time(MST 31d),and increased the ratio of CD4~+ CD25~+ to CD4~+ T lymphocytes both in serum and spleen tissue in apoptotic cell infusion group versus infusions of normal cell, necrotic cell and Hanks solution at 7 days after the infusion (all P0.05). Conclusions Transfusion of donor apoptotic splenocytes can induce rat immunological tolerance to allogenic islets transplantation, and CD4~+ CD25~+ T lymphocytes have an important role in inducing the tolerance.