中文摘要：

目的探讨EntransterTM-CD25siRNA纳米粒对大鼠高危角膜移植术后免疫排斥反应的抑制及延长角膜植片存活时间的作用。方法以SD大鼠为受体（n=96）,Wistar大鼠为供体（n=48）。受体右眼碱烧伤后14d行穿透性角膜移植手术。术后将大鼠随机分为阴性对照组（A组）、对照siRNA治疗组（B组）、治疗1组（C组,术后2h给予EntransterTMCD25siRNA复合物点眼）、治疗2组（D组,术后2h和术后第7天给予EntransterTM-CD25siRNA复合物点眼）,每组24只。裂隙灯下观察大鼠角膜情况并对其排斥反应进行评分,HE染色检测角膜组织病理学变化,透射电镜观察植片超微结构改变,免疫组化和荧光定量PCR法检测角膜CD25的表达。结果与A、B组比较,C、D两组角膜植片存活时间明显延长,差异有统计学意义（P〈0.05）。HE染色显示A、B组角膜植片增厚、水肿,胶原纤维排列紊乱,大量炎性细胞浸润;C、D组植片排斥程度较A、B组明显减轻。免疫组化染色显示各组角膜上皮层、基质层、内皮层均有CD25表达,且在A、B组中的表达明显多于C、D组。透射电镜观察显示C、D组角膜植片基质层成纤维细胞凋亡及坏死较A、B组减轻,超微结构改变具有明显差异。荧光定量PCR检测显示A、B两组角膜植片中CD25 mRNA的表达明显高于C、D组,差异有统计学意义（P〈0.05）。结论 CD25siRNA纳米粒可减轻角膜移植术后的免疫排斥反应并有效延长角膜植片存活时间。

英文摘要：

Objective To investigate the effects of CD25 siRNA nanoparticles against immune rejection and prolongation of corneal graft survival time after high-risk corneal grafting in rats. Methods Orthotopic corneal transplantation was performed in SD rats with alkali burned corneas to mimic high-risk rat models. Donor cornea（Wistar rats） was grafted into the right cornea of SD recipients on day 14 after alkali burn. The grafted rats were randomly divided into control group（Group A）, EntransterTMcontrol CD25 siRNA instillation treatment（Group B）, EntransterTM-CD25 siRNA instillation treatment（Group C） and EntransterTMCD25 siRNA twice instillation treatment（Group D, first administration at 2-hour post-surgery and second on day 7 post-surgery）. The recipient eyes were examined using a slit lamp microscope. Then, the mean survival time and rejection index（RI） were calculated. The morphologies of grafts were microscopically examined with HE staining, and TEM. CD25 expression after operation was determined by quantitative RT-PCR and immunohistochemistry. Results The survival curves of transplanted cornea showed that the mean survival time in rats of groups C and D was significantly longer than that in groups A and B（P〈0.05）. No significant difference was found in survival time between group A and group B, and the same between group C and group D. The grafts in groups A and B showed obvious edema and thickening, with irregular arrangement of collagen fibers and infiltration of a large amount of inflammatory cells. Immunohistochemical results showed that expression of CD25 was found in the corneal epithelium, stroma and endothelium in all rats, and higher CD25 expression was observed in groups A and B. Transmission electron microscopy revealed that the degree of stromal fibroblast apoptosis and necrosis in corneal graft was obviously lower in groups C and D than that of groups A and B, with a significant statistical difference. The expression of CD25 mRNA in the experimental group was significantly