Irradiation for Ex vivo graft to prevent the small-bowel rejection

排斥反应时，PPS中HEV上MAdCAM-1的表达下调。相反，在排斥反应期间，其在固有腔血管内皮细胞上的表达上调。移植后第5天，移植物中Fas和FasL阳性的肠上皮细胞数明显多于未移植对照组。同样，在移植后第5天，PPS中Fas和FasL阳性的单个核细胞也显著增加。MAdCAM-1表达的改变可能与SB移植物排斥反应的发生有关。Sb移植物排斥反应过程中FES/FasL系统的激活可能与Sb移植物排斥反应的发生有关。我们还研究了体外移植物照射和FTY720的影响。FTY720模型和体外照射+FTY720模型移植物存活时间延长。在FTY720模型和体外照射+FTY720模型中，PPS中HEV上MAdCAM-1的表达和PPS中Fas/FasL阳性的单个核细胞数均减少，提示体外照射+FTY720对控制SB移植物排斥反应具有重要意义。

MAdCAM-1 expression on HEVs in PPs was down-regulated during rejection. In contrast its expression on endothelial cells of vessels in the lumina propria was up-regulated during rejection. On day 5 the number of Fas- and FasL-postive enterocytes were increased significantly in the allografts compared with the nontransplanted controls. Similarly, in the PPs, Fas- and FasL-positive mononuclear cells also increased significantly on day 5 in the allografts. Alteration in MAdCAM-1 expression may be associated with the development of SB graft rejection. Activation of fes/FasL system occurred during SB graft rejection suggest that it may be associated with the development of SB graft rejection.We also studied about the effect of ex vivo graft irradiation and FTY720. Graft survival was prolonged in FTY720 model and ex vivo graft irradiation +FTY720 model. In FTY720 model and ex vivo graft irradiation +FTY720 model, the number of the expression of MAdCAM-1 expression on HEVs in PPs and, Fas/FasL-positive mononuclear cells in the PPs were decreased.These findings suggest that ex vivo graft irradiation +FTY720 is important for the control of SB graft rejection.