Inhibitory effect of high expression of IDO from donor DCs on allograft rejection in mice heterotopic cardiac transplantation model

Objective To investigate the effect of high expression of functional IDO trom donor DCs on transplantation rejection in mice heterotopic cardiac transplantation.Method Adenovirus vector containing IDO gene was used to infect donor (C57BL/6) DCs to obtain IDO+ DCs.Mouse heterotopic cardiac transplantation models were established (C57BL/6-BALB/c) and the following groups were set up:control group,DCs injection group and IDO+ DCs injection group.Survival time of the donor heart in all groups was observed.Meanwhile,donor hearts were harvested at 7 th day post-transplantation for different examinations,including pathological examination,mRNA expression of IDO by real-time PCR,and IDO protein expression by Western blotting.Peripheral blood of recipients was also harvested for T lymphocyte apoptosis rate examination by FACS.Result Cardiac allograft median survival time in control group,DCs injection group and IDO+ DCs injection group was 7,7.5,and 17.5 days respectively.IDO+ DCs treatment significantly prolonged the survival time of donor hearts (P＜0.01).Pathological grading was significantly decreased (P＜0.01).The CD3+ T lymphocyte apoptosis rate in peripheral blood of recipients in IDO+ DCs injection group was (46.50 + 5.02)％,significantly higher than the other two groups (P＜0.01).Both IDO mRNA and protein expression showed significant increase (P＜0.01).Conclusion The preoperative medication with IDO+ DCs injection to the recipients could induce T lymphocyte apoptosis and significantly suppress the rejection in mice heterotopic cardiac homotransplantation. Key words: Mouse;  Heart transplantation;  IDO;  Dendritic cell;  Rejection