Expression of cytokine in mouse graft of corneal allograft rejection

Abstract

Background Cytokines play a crucial role in mediating immune tolerance or immune rejection of corneal transplantation.However,the study on the expression of cytokines in corneal graft is seldom.ObjectiveThe purpose of the study is to investigate the change of cytokine expression in allografts at different time points after corneal transplantation.Methods BALB/c and C57BL/6 mice aged 6 to 8-week old were used to establish autologous and allografts keratoplasty models.BALB/c mouse was use as donor and receipt in autologous group,and the cornea of C57BL/6 mouse was used to graft on the BALB/c mouse in the allografts group.The graft inflammation was clinically scored,and graft inflammatory scores of ≥5 or opaciflcation scores of ≥2 were identified as rejection.BALB/c mice were randomized into normal control group(3 mice)and allografts group(15 mice).Reverse transcriptPCR (RT-PCR) was used to detect the expression of interleukin-4 (IL-4) mRNA,interferon-γ (IFN-γ) mRNA,IL-10mRNA and tumor necrosis factor(TNF-α) mRNA in graft 6 hours and 1 day,3,7,14 days after operation.Results The corneal graft opacification score was ＜2 and inflammatory score was ＜5 in the 10 mice with autologous keratoplasty until 60 days with the survival rate 100％.The edema,opacification and new blood vessel were seen in the BALB/c mice received allografts keratoplasty.The inflammatory score was ≥ 5 and the opacification score was ≥2 24 days after surgery with the rejection rate 100％,in the allografts group,and the graft survival time was (17.80±4.66)days.RT-PCR showed that IL-4 and IFN-γ were positively expressed,and IL-10 and TNF-α were absently expressed in normal mouse cornea.In the allografts keratoplasty mice,positive responses for IL-4,IFN-γ and IL-10 were found in 6hours after operation,but TNF-α was absent.From 1 day through 3 days after operation,the expressions of IL-4,IFN-γand TNF-α were enhanced but IL-10 was disappeared in the graft.IL-10,IFN-γ and TNF-α were expressed till the 7th day,but on the 14th day,only IL-10 was detected in graft in the allografts keratoplasty mice.Conclusions TNF-αis a main factor among the variety of cytokines that may influent corneal allograft rejection locally. Key words: Corneal transplantation; Immunity; Rejection; Tolerance; Cytokine