Aims: It is increasingly recognized that expression of cytoprotective genes in grafts can affect the progress of chronic allograft nephropathy (CAN). Little is known about the influence of different immunosuppressive regimens on expression of cytoprotective genes in allografts undergoing CAN. We investigate whether there is difference between rapamycin (Rapa) and FK506 in the expression of cytoprotective genes in rat kidney allografts undergoing CAN.
Methods: Sprague-Dawley rat renal grafts were orthotopically transplanted into Wistar rats following the procedure of Kamada with our modification. The recipients were divided into three oral treatment groups: group 1: vehicle group (cyclosporine [CsA] 10 mg/kg.dx 10 days followed by vehicle); group 2: Rapa group (CsA 10 mg/kg.d x 10 d followed by Rapa 0.8 mg/kg.d); group 3: FK506 group (CsA 10 mg/kg.d x 10 d followed by FK506 0.15 mg/kg.d). At the same times after transplantation, the rats were sacrificed to harvest the renal allografts. The expression of four cytoprotective genes, A20, heme oxygenase (HO)-1, Bcl-2, and Bcl-X/L were analyzed in these grafted kidneys by quantitative reverse transcriptase polymerase chain reaction and immunohistochemistry.
Results: Four cytoprotective genes were all detected in rat kidney allografts undergoing CAN. The expression of A20 in the Rapa group was significantly higher than that in the FK506 or the vehicle group (P < .05). There was no significant difference between the Rapa group and FK506 group in the expressions of HO-1, Bcl-2, and Bcl-X/L.
Conclusions: We demonstrate that various immunosuppressive agents have different effects on the expression of cytoprotective genes.