Studying Of Allogeneic Bone Marrow Stem Cell Transplantation To Induce Tolerance In NOD Mice

Objective:To investigate immune tolerance induced by allogeneic bone marrow stem cell transplantation in NOD mice and the underlying mechanism.Methods:Established a model of allogeneic bone marrow stem cell transplantation in NOD mice,recipients was NOD mice,donors were C57BL/6 male mice(H-2b).twenty one NOD mice(six week old)were randomly divided into groups A and group B with eleven and ten mice respectively.Group A as control group that was not received any intervention.Group B received total body irradiation(TBI)9.5cGy,four hours after TBI,mice of group B were transplanted with bone marrow cells from donor mice via tail vein.All the mice were killed and their spleen lymphocytes were collected.The proportion of CD3+,CD4+,CD8+T cells,CD11C+DC,CD11C+B220-mDCs, CD11C+B220+pDCs and CD4+CD25+ regulator T cell were analyzed by flow cytometry.The serum levels of cytokines IFN-γwere determined by enzyme-linked immunosorbent assay(ELISA).Results:The incidence rate of diabetes in group B was obviously lower than that in group A(20%vs.72.7%,P＜0.05).ELISA tested revealed that lower levels of IFN-γin group B compared with group A(73.25±9.6 ng/L vs. 124.08±22.47ng/L,P＜0.01).The number of pDC subsets in splenocytes of group B was higher than those of group A(1.81±1.02vs0.73±0.39,P＜0.05),the number of CD8+T cells in splenocytes of group B was higher than those of group A(14.3±4.26vs9.86±2.75,P＜0.05),and the number of CD4+CD25+ regulator T cells in splenocytes of group B was higher than those of group A(4.97±1.77vs1.99±1.19,P＜0.01).but the number of mDC subsets in splenocytes of group B was lower than those of group A(3.30±1.39 vs. 6.74±3.14,P＜0.05).The number of CD3+,CD4+ T cells,DC subsets in showed no significant difference between those two groups(P＞0.05).Conclusions:Early application of bone marrow stem cell transplantation can reestablish cellular immunity,reduced and delayed the incidence of diabetes in NOD mice.The mechanism may be related to the breakdown of disordered immune system and the rebuilding cellular immunity to induce immune tolerance,and restore the balance between Th1/Th2 cytokines.