CD4和CD8基因敲除鼠行穿透性角膜移植术后免疫排斥特征的研究

目的　探讨CD4和CD8基因敲除小鼠行穿透性角膜移植术后免疫排斥反应发生的机制。方法　CD4、CD8基因敲除小鼠及C57BL/6小鼠各20只,分成3组,右眼接受穿透性角膜移植术,供体为BALB/c小鼠,术后裂隙灯显微镜评价角膜移植片情况,并详细记录免疫排斥的发生时间,在术后1、2、4周各取2只鼠术眼行免疫组织化学检查,观察眼前段CD+4 、CD+8 T细胞的变化。在术后2周, 3组小鼠各选其中10只接受皮肤移植,供体为BALB/c小鼠,监测皮肤移植后皮肤植片免疫排斥反应的时间和在皮肤发生排斥反应时角膜移植片的情况。结果　3组小鼠角膜移植术后免疫排斥发生时间明显不同,CD4基因敲除鼠角膜移植片保持透明,至少观察了90d未见免疫排斥反应发生;CD8基因敲除小鼠在(28±3)d时发生免疫排斥反应;C57BL/6小鼠发生免疫排斥反应的时间为(14±2)d(F=2034, P<0. 01)。移植皮肤后发生免疫排斥反应时间为:CD4基因敲除鼠(14±2)d,CD8基因敲除鼠(12±1)d,C57BL/6小鼠(10±1)d(F=42. 54, P<0. 01)。结论　小鼠行穿透性角膜移植术后免疫排斥反应可能是以T淋巴细胞,主要为CD+4 T细胞介导的免疫排斥反应,CD+8 T细胞参与了排斥反应过程。

The corneal allograft rejection features in CD4 and CD8 knock-out mice

OBJECTIVE: To study the mechanism and the features of corneal allograft rejection using a model of CD4 and CD8 knock-out mice. METHODS: The mice were divided into three groups with 20 mice in each group. CD4 knock-out mice, CD8 knock-out mice and C57BL/6 mice were used as recipients and BALB/c mice as corneal graft donors. Postoperative evaluation included slit-lamp biomicroscopy and immunohistological studies. The rejection times were recorded and the cytokines in the eye after the surgery were measured at 1 week, 2 weeks and 4 weeks after the transplantation. Thirty mice (each group ten mice) received skin transplantation using BALB/c as donors in the second week after penetrating keratoplasty. The time of skin grafts rejection was recorded and the cornea grafts were inspected when the skin grafts were rejected. RESULTS: The rejection time varied in these three groups. The corneal grafts in CD4 knock-out mice were clear and no rejection occurred > 90 days. The corneal grafts in CD8 knock out mice were rejected at (28 +/- 3) days. The grafts in the control groups were rejected at (14 +/- 2) days (F = 2034, P < 0.01). The skin grafts rejection were recorded at (14 +/- 2), (12 +/- 1), (10 +/- 1) days in CD4 knock-out mice, CD8 knock-out mice and control groups, respectively (F = 42.54, P < 0.01). CONCLUSIONS: CD4 and CD8 knock-out mice are useful models for studying of corneal graft rejection. The cornea allograft rejection after penetrating keratoplasty is mediated primarily by CD(4)(+) T lymphocytes. The CD(8)(+) T lymphocytes also participate in the rejection processes.