The Cells And Factors Involving In Graft Arteriosclerosis In Rat Allogenic Orthotopic Abdominal Aortic Transplantation

Objectives Chronic graft dysfunction is the greatest challenge to long-term graft survival although the immediate outcome in organ transplantation has been greatly improved. Graft arteriosclerosis is the common feature in chronic graft dysfunction (CGD) . Many observations suggested that recipients' progenitor cell participate in the development of neointima of graft arteriosclerosis. This study is to investigate the role of recipients' cell in endothelium repairing and remodeling after its prolonged cold preservation injury, whether Cyclosporin A could affect this process via endothelium protection by immunosuppression. The VEGF expression in preceding processes is included.Methods The male Sprague-Dawley rats were performed orthotopic abdominal aortic transplantation from female Wistar rat and divided into three groups (n=35 each group), graft preserved for 48 hours in 4°C UW solution in prolonged cold ischemia group (PCI group) and for <1 hour in control group, and graft preserved for <1 hour but recipient rats fed with Cyclosporin A 5mg/kg/d in Cyclosporin A group(CsA group).Harvesting 5 grafts at 1 day, 1 week, 2 weeks, 3 weeks, 4 weeks, 2months and 3 months following operation in 3 groups, respectively. And measure the thickness of neointima of graft aortas in HE dying and the direct in situ polymerase chain reaction (ISPCR) was established using SRY gene as a marker, which locates on Y-chromosome. The SRY gene positive cell was identified by light microscopy (LM). And the VEGF expression was examined in 3 groups by immunocytochemistry.Results SRY-positive cells from recipients were characterized by black point in nucleus. The SRY-marked endothelial cells and smooth muscle-like cells were identified in neointima 2 weeks following transplantation in PCI group, while 4 weeks in control group. The higher chimeric rate of endothelial cells and smooth muscle-like cells was observed in PCI group than control group. The neointima in PCI group is thicker than control group at same time-point. Prolonged cold preservation could simulate the stronger neointima proliferation.The VEGF expression was detected at 1 week, 2weeks and 3 weeks following transplantation in control group; the weak expression was kept in PCI group; while the weak but continuing expression was detected in CsA group.Conclusions Our data suggests that the direct in situ PCR is a valuable method to investigate the cells derived from the male recipients and the prolonged cold preservation could accelerate the neointimal formation and promote the recipients' cell participating in graft arteriosclerosis. The recipients' cells incorporated into neointima of arteriosclerosis by repairingimpaired graft following endothelium injury and resulted in chimeric repair. Further quantitative methods will help to specify the lineage and quantity of recipients' cells involving neointima development of graft arteriosclerosis. The Cyclosporin A alleviated the recipients' cells participating in repairing injured endothelium by protection of graft endothelium via immunosuppression of host immunological system.VEGF is crucial for neointima. But our data suggests that the VEGF expression is- related to endothelium injury and little association with impair repairing following endothelium injury.