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Graft rejection is a primary cause of corneal transplantation failure, especially in high-risk keratoplasty.How to extend the survival time of graft is a problem to be solved.
This study was to investigate the influence of immune tolerance on high-risk rat keratoplasty induced by donor bone marrow-derived immature dendritic cells (imDCs) transfected by chemokine receptor 7 (CCR7) recombinant adenovirus (Ad).
Bone marrow-derived imDCs were isolated and cultured from femur marrow of one male Wistar donor rat.The cells were transfected using recombinant Ad vector with rat CCR7 gene and resuspended in 500 μl PBS containing 1% fetal bovine serum with the cells 1×107.High-risk corneal transplantaion models were established using monolateral corneal alkali-burn method in 60 SD rat recipients, and then allograft keratoplasty was performed with the 30 Wistar rats as donors.The models were randomized into the PBS group, imDCs group, imDCs with blank Ad vector group and imDCs with Ad-CCR7 group following the corresponding solution injection via caudal vein on preoperative day 7 and postoperative day 3 respectively.The survival time of graft was evaluated under the slit lamp microscope once per day.On the 14th day after operation, corneal sections were prepared from 6 eyes of each group for the pathological examination, and the relative expression levels of T helper cell 1 (Th1)-related factors, interleukin-2 (IL-2) mRNA and interferon-γ(IFN-γ) mRNA, as well as Th2-related factors, IL-4 mRNA and IL-10 mRNA, were detected by reverse transcription PCR (RT-PCR). The use and care of animals complied with the ARVO statement
The mean survival time of grafts was (10.44±1.88), (16.00±2.18), (15.11±2.03) and (23.67±2.83) days in the PBS group, imDCs group, imDCs with blank Ad group and imDCs with Ad-CCR7 group, respectively, with a significant difference among the 4 groups (F=53.005, P=0.000). Compared with the PBS group, the mean survival time of grafts was considerably extended in the imDCs group, imDCs with blank Ad group and imDCs with Ad-CCR7 group (t=5.220, 4.385, 12.423, all at P=0.000), and a remarkble prolongation of graft survival duration was seen in the imDCs with Ad-CCR7 group in comparison with the imDCs group and the imDCs with blank Ad group (t=7.204, 8.039, both at P=0.000). The relative expression levels of IFN-γ mRNA and IL-2 mRNA in the grafts were significantly lower, but the relative expression levels of IL-4 mRNA and IL-10 mRNA were significantly higher in the imDCs group, imDCs with blank Ad group and the imDCs with Ad-CCR7 group than those in the PBS group (all at P<0.05). Compared with the imDCs group and the imDCs with blank Ad group, the relative expression levels of IFN-γ mRNA and IL-2 mRNA in the grafts were remarkably delined, but the relative expression levels of IL-4 mRNA and IL-10 mRNA were remarkably elevated in the imDCs with Ad-CCR7 group (all at P=0.000).
Application of imDCs transfected with CCR7 recombinant Ad via vena caudalis can prolong the survival time of grafts after keratoplasty of SD rats probably by affecting the balance of Th1/Th2 cytokines.