环孢素A缓释系统植入前房抑制鼠角膜移植免疫排斥反应机制的研究

目的　探讨前房植入环孢素A(cyclosporineA ,CsA)缓释系统抑制鼠角膜移植免疫排斥反应的机制。方法　 (1)环孢素A缓释系统的制备 :为CsA粉剂与已交酯 丙交酯 已内酯的三元共聚物混合体 ,每粒含环孢素A 0 5mg。 (2 )对 90只 (90只眼 )BALB c鼠 (受体 )行穿透性角膜移植术 ,将其分为A、B、C组 ,每组 30只。供体为C5 7BL 6鼠。A组术中鼠前房植入CsA缓释系统 ;B组术中鼠前房植入不含CsA的空白缓释系统 ;C组术后不作任何处理作为正常对照组。术后 3d用裂隙灯显微镜观察角膜植片情况 ,记录角膜植片免疫排斥反应发生的时间和程度。各组分别于术后 1、2、4及 6周随机取 2只鼠眼行组织病理学检查 ,并用CD4、CD8及CD11B单克隆抗体行免疫组织化学染色 ,观察各组T淋巴细胞的迁移和数量。结果　A组鼠角膜植片排斥时间平均 (35± 3)d ,较B、C组 (14± 3)d明显延长 (P <0 0 0 1)。前房植入的CsA缓释系统体积缩小前 ,A组角膜植片均保持透明 ;当前房植入的CsA缓释系统消失后 ,角膜出现免疫排斥反应 ,植片逐渐混浊、增厚、血管化。B、C组免疫排斥反应均在术后 2周发生。组织病理学和免疫组织化学检查 :A组在术后 14d仅于植床角膜可见少量CD+ 4 　和CD+ 8　细胞浸润 ,在虹膜和睫状体中未见CD+ 11B、CD+ 4 、CD+ 8　T淋

Prolongation of corneal allograft survival in mice with a cyclosporine drug delivery system implant

OBJECTIVE: To study the immunosuppressive effect and mechanism of cyclospoirne A (CsA) in a drug delivery system (DDS) implanted in the anterior chamber of corneal allograft in a mouse model. METHODS: Female BALB-c mice were the recipients of corneal allografts from C57BL-6 donor mice. A total of 90 allografts were implanted in penetrating keratoplasty. Cyclosporine A was incorporated into a polyactide-coglycolide-co-caprolactone (PGLC) polymer and small pellets of CsA PGLC were placed into the anterior chamber of recipient mouse eyes at the time of transplantation. Control recipients did not receive any implants or received implants containing no drug. The clinical condition of the grafts was observed by slit-lamp microscope every three days and the tempo and the time of rejection of the grafts were recorded. Some grafts were removed at weekly intervals for histopathological and immunohistopathological analysis. RESULTS: The corneal allografts of the mice with CsA PGLC implanted (group A) prolonged their survival time significantly with a median of 35 +/- 3 days. In contrast, the median survival time of corneal allografts in eyes of recipients receiving implants containing no drug (group B) and eyes receiving allografts but no implant (group C) was 14 +/- 3 days. The differences between A and B and between A and C group were statistically very significant (P < 0.001). The corneal donor of the eyes treated with the CsA PGLC implant remained clear until the implant pallet began to shrink in size and graft rejection began. The grafts which came under an immune attack progressively were vascularized and thickened, and became opaque. In the control animals, the development of the immune response overlapped with the acute inflammatory reaction, which occurred in the mouse eye following corneal transplantation. Histopathologically and immunohistopathologically, the grafts, ciliary body and iris which were subjected to an immune response contained a dense infiltrate of neutrophils, CD(4)(+) and CD(8)(+) T lymphocytes, and many CD(11B)(+) inflammatory cells including macrophages and Langerhans cells in the control rejection mice. This cellular infiltrate was decreased in the recipients, and delayed in ciliary body and iris whose corneas were transplanted with the CsA PGLC implant in the anterior chamber. CONCLUSION: Intraocular CsA in a sustained release system as a means significantly prolongs corneal allograft survival in mouse model and protests corneal allografts from acute, immune-mediated rejection.