| Research Abstract |
Inbred rats (Lewis and Brown Norway) of 10 to 12 week after birth were used as experimental animals. A fresh aortic graft was implanted orthotopically in the infrarenal aorta. A cryopreserved aortic graft was implanted orthotopically after programmed freezing followed by 1-week preservation in a nitrogen tank. Dendritic cells were sporadically seen in the adventitia of a fresh pre-implant aortic graft, and MHC class I antigen was also slightly positive. There was no dendritic cell seen in a cryopreserved pre-implant aortic graft, and MHC class I was slightly positive. Scanning electron microscope examination showed deformity and disarray of endothelial cells, but deendothelialization was not remarkable. Four aortic implantation models were created ; 【encircled 1】Syngeneic implantation of fresh graft, 【encircled 2】Syngeneic implantation of cryopreserved graft, 【encircled 3】Allergenic implantation of fresh graft, 【encircled 4】Allergenic implantation of cryopreserved graft. Ten implantati
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ons were performed in each group, which were divided to 2 groups (Group A : sacrificed 2 weeks after implantation, and Group B : sacrificed 1 month after implantation, 5 cases for each). All grafts were patent in both groups of syngeneic implantation. In fresh-allogeneic implant model, 3 grafts were patent in Group A, and only 1 graft was patent in Group B. All grafts were patent in both groups of cry-allogeneic implant model. Microscopic examination of explanted syngeneic graft showed mild inflammatory cell infiltration in the adventitia. There was no significant difference in the distribution of dendritic cells from pre-implantation observation. Reendothelialization was seen in cryo-syngeneic model. In cryo-fresh model, strong infiltration of inflammatory calls including many dendritic cells was detected. There was marked expression of ICAM-1, MHC class I and class II antigens. Although inflammatory cell infiltration was seen in the adventitia of cryo-allogeneic model, there were scarce dendritic cells. whereas expression of MHC class I antigen was strong, class II antigen was expressed weakly, showing that rejection of allogeneic aorta was almost suppressed. Less
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