Objective: To observe the effect of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) on the allograft rejection after ex vivo adenovirus-mediated gene transfer to cornea.
Methods: By co-culture with corneal graft, a replication-deficient adenovirus encoding the mTRAIL gene (Ad-TRAIL) was transduced into graft endothelium of mice. Immunohistochemistry was used to look for the TRAIL protein expression in ex vivo corneal endothelium. The grafts obtained from C57BL/6 mice that carried Ad-TRAIL were transplanted into the eyes of BALB/c mice. The occurrence time, the intensity of immunorejection and the immersion of CD4(+) and CD8(+) T lymphocytes were observed. TUNEL was used to detect the cell's apoptosis in the corneal grafts. We used uninfected group, Ad-green-fluorescent protein (GFP) transduced group and soluble death receptor 5 (sDR5) group as controls.
Results: TRAIL protein expression was seen on more than 50% of endothelium 3 days after Ad-TRAIL transduced into corneal grafts in vitro, with higher expression for 2 weeks, then gradually reduced to negative till 3 weeks. The mean time of allograft rejection was 17.7 days in uninfected group, 22 days in Ad-TRAIL group, 17.4 days in Ad-GFP group and 12.3 days in sDR5 group. The differences among four groups were statistically significant. There were distributions of CD4(+), CD8(+) T lymphocytes and apoptotic cells in all rejected corneal grafts.
Conclusions: TRAIL protein can inhibit corneal allograft rejection in mice and prolong the survival time of transplanted allografts.