高危角膜移植大鼠排斥反应及VEGF-C/D表达的研究

目的：探讨鼠角膜碱烧伤后VEGF-C/D的表达和意义,以及新生淋巴管在高危角膜移植后排斥反应中的作用。
　　方法：制作角膜碱烧伤模型,取不同时间段角膜进行电镜观察,观察角膜血管化情况；采用免疫组织化学方法检测l、3、5、7、14、28 d角膜组织VEGF-C/D及VEGFR-3的表达；并在角膜中仅有血管(A组),同时存在新生血管及新生淋巴管(B组),新生淋巴管消退期(C组),角膜新生血管消退期(D组)以及正常组(N 组)进行穿透性角膜移植,比较不同角膜植片的排斥反应指数( rejection index, RI)值及存活时间。
　　结果：电镜观察发现,在碱烧伤后第7d时鼠角膜出现新生血管,未出现新生淋巴管,在碱烧伤2 wk时出现新生血管的同时出现淋巴管,5wk时无明显的新生淋巴管,8wk时新生血管逐渐消退；大鼠角膜组织中 VEGF-C/D 及VEGFR-3的表达从第3 d开始明显上升,并于第5 d达到最高峰。角膜移植后N、A、B、C、D组的植片平均存活时间分别为14.25±0.62、9.35±1.02、5.06±1.13、8.71±0.83、9.44±1.05d。组间比较发现,B组植片平均存活时间显著性缩短(P<0.05),A、C、D的存活时间均显著性延长(P<0.05)。
　　结论：角膜碱烧伤后存在VEGF-C/D及VEGFR-3的高表达,而且新生淋巴管能加速高危角膜移植后的免疫排斥反应。

Study of high-risk corneal transplantation rejection and the expression of VEGF-C/D

AIM: To investigate the expression and the significance of VEGF-C/D in rat cornea after alkali burning as well as the role of lymphangiogenesis in the high-risk corneal transplantation rejection.

METHODS: The model of alkali burn corneal was made. Different times corneas were taken to electron microscope for vascularization, and examined the expression of VEGF-C/D and VEGFR-3 in l, 3, 5, 7, 14, 28d. The other rat cornea after alkali burn were divided into four parts to penetrate keratoplasty, containing only blood vessels in the cornea(group A), angiogenesis and lymphangiogenesis(group B), lymphangiogenesis degenerating period(group C), angiogenesis degenerating period(group D). In addition, there are also normal groups(group N)to compare the RI values and survival time of corneal graft.

RESULTS: Electron microscopy showed that, when the first 7d rat cornea appeared neovascularization after alkali burn, but not lymphangiogenesis. The occurrence of new blood vessels and lymphatic in 2wk. There were no obvious lymphangiogenesis in 5wk and the angiogenesis gradually subside in 8 wk. The expression of VEGF-C/D and VEGFR-3 in the corneas of rats were up-regulated in the third days after the injury, and reached its peaks at 5d. The average survival time of group N, A, B, C, D were(14.25±0.62)d,(9.35±1.02)d,(5.06±1.13)d,(8.71±0.83)d,(9.44±1.05)d after transplant cornea. Compared to the rest of the group, group B plant average survival time significantly shortened(P<0.05), while compared with group B, the survival time of A, C, D groups were significantly longer(P<0.05).

CONCLUSION: VEGF - C/D and VEGFR-3 are expressed significantly after corneal alkali burn. New lymphatic vessels can accelerate high-risk corneal transplantation immune rejection.