The Prevention Of Pregnancy-induced Regulatory T Cells On Cardiac Allograft In Mice

Objective To study the role of pregnancy-induced regulatory T cells (piTregs) on the prevention of cardiac allograft.Methods All recipient mice (C57BL/6(?)) were divided into three groups:Control group,Treg group,PiTreg group. Prior to adoptive cell transfer, recipient mice received 2Gy whole body irradiation. The day before cardiac graft, Tregs (5×105/200μl PBS) from C57BL/6♀were injected (i.v.) to recipient mice in Treg group. PiTreg group were injected piTregs (5×105/200μl PBS) from mid-pregnany C57BL/6♀mating with BALB/c(?)and Control group were saline by the similar route respectively. Post operation, survival time, histological changes of allograft, chimerism in spleen and cytokines in serum of the recipients were measured.Results (1) Marked 40d post-operation as the end, the survival time of cardiac allografts in Treg group(40±0d, n=6)and PiTreg group(40±0d, n=6) were significantly longer than Control group (9.67±0.58d, n=3), p<0.01). (2) Post-operation 10d, the inflammatory cells infiltrated in cardiac allografts of Treg group and PiTreg group reduced sharply, comparing with Control group. (3) Chimerism in the PiTreg group (5.48±1.04%) definitely increased larger than Treg group (1.42±0.28%), p=0.029.(4) In the PiTreg group and Treg group, proportion of Tregs in CD4+T cells in recipient spleen were augment as well as proportion of Foxp3+ in CD4+T cell, while the former was significance. (5) In the PiTreg group and Treg group, the cytokine in serum mentioned with rejection such as MIG,RANTES decreased comparing to the Control group, while the difference between these groups was unsignificant.Conclusion piTreg/Treg play a vital role on the prevention of cardiac allografts. And the mechanism may refer to the formation of chimerism, the augmentation of Tregs/CD4+T cells and Foxp3+/CD4+T cells in recipient spleen and the incline of the cytokines in serum.