Inhibition of MD-1 Expression by Immunosuppressants or Antisense Oligodeoxynucleotides on Skin Allograft Survival in Mice

Abstract

Aim The aim of this study was to investigate the effects of inhibition of MD-1 expression using nonspecific immunosuppressants and specific antisense oligodeoxynucleotides (AS-ODNs) treatment on skin allograft survival in mice. Methods C57BL/6 to Balb/c skin allograft model was used in all groups, followed by Cyclosporine (CsA), Tacrolimus (FK506), Mycophenolate Mofetil (MMF), and Sirolimus (SRL) intraperitaneally, as well as AS-ODNs intravenously. Recipients were humanely killed at 11 days after transplantation. MD-1 expression was determined using flow cytometric analysis (FACS). AlamarBlue was used to evaluate proliferation. And serum levels of interleukin (IL)-2 and IL-10 were detected using enzyme-linked immunosorbent assay (ELISA). Results Compared with saline controls, the mean survival times (MST) of skin allografts in all of the immunosuppressants and AS-ODNs treated groups were significantly prolonged ( P < .05). CsA, MMF, and AS-ODNs inhibited MD-1 expression and lymphocyte proliferation, as well as decreased serum level of IL-2 and increased that of IL-10; FK506, treatment showed all the effects mentioned above but up-regulated the IL-10 level; SRL had no significant influence on either MD-1 expression or IL-2 and IL-10 level, although it equally suppressed the proliferation ( P < .05 vs controls). The negative correlation between MD-1 expression and lymphocyte proliferation or IL-2 level was significant, as was the positive correlation between it and IL-10 level ( P < .01). Conclusions CsA, FK506, MMF, and AS-ODNs can efficiently inhibit MD-1 expression. The effects of the immunosuppressants are seemingly associated with the down-regulation of the IL-2 serum level. MD-1 was theorized to play an important role in rejection promotion, although the precise relationship between it and allograft survival still remains ambiguous.