Short-term immunosuppression after rat parathyroid allotransplantation

The aim of this study was to evaluate whether short-term postoperative immunosuppression is able to sufficiently prolong graft survival after experimental allogeneic parathyroid transplantation. Heterotopic parathyroid transplantation was performed in 6 groups: 1) syngeneic control Lewis (LEW) to LEW; 2) allogeneic control Wistar-Furth (WF) to LEW; 3-5) WF to LEW plus short-term immunosuppression, postoperative days 1-13 (cyclosporine 5/10/20 mg/kg); and 6) WF to LEW plus 10 mg/kg CyA from preoperative day 7 to postoperative day 7. Graft function was examined up to 60 days; histological and immunohistological examination was performed on all grafts with impaired function. Graft function after syngeneic transplantation was indefinite, while recipients of allogeneic grafts turned hypocalcemic after 13 +/- 2 days. With immunosuppression, graft function was 21 +/- 2 days (groups 5 and 6) and 28 +/- 3 days (groups 3 and 4). Histologically, a cellular infiltrate responsible for graft destruction was found. The results show that indefinite parathyroid allograft survival cannot be achieved by short-term immunosuppression alone. Whether the combination of an additional graft pretreatment and immunosuppression has an impact on graft function will be further examined.