白细胞介素1受体拮抗剂对大鼠角膜移植物中细胞凋亡的影响

目的:观察急性排斥反应期大鼠角膜移植物中细胞的凋亡,探讨白细胞介素1受体拮抗剂(IL-1ra)对细胞凋亡的影响。方法:建立大鼠穿透性角膜移植模型。实验分为4组,即正常Wistar大鼠(A组),同基因(Wistar大鼠→Wistar大鼠)角膜移植组(B组),同种异体(Wistar大鼠→SD大鼠)角膜移植生理盐水处理组(C组)及IL-1ra治疗组(D组)。应用TUNEL染色法,检测术后7、10及14d各组角膜植片中细胞的凋亡,并对染色结果采用全自动图像分析系统处理后,计算阳性单位(PU)值。制备正常角膜及角膜植片的电镜标本,在透射电镜下观察角膜植片中细胞超微结构的变化。结果:(1)C组角膜植片的平均存活时间为(10.38±1.85)d;而D组为(13.56±1.94)d,二者差异具有统计学意义(P<0.01)。(2)与正常角膜和未发生排斥反应的角膜植片相比较,发生排斥反应的角膜植片中细胞的超微结构改变主要表现为细胞凋亡和细胞坏死共存的特征。(3)正常角膜上皮细胞层中仅有极少数凋亡的细胞,基质层及内皮细胞层中几乎无凋亡的细胞。术后1周,B、C和D组的角膜植片中的各层中均可见散在的细胞凋亡,各组的平均PU值差异无统计学意义(P>0.05)。急性排斥期C组和D组的角膜植片在伤口附近及中央区凋亡的细胞均明显增多,尤其是C组,凋亡的细胞主要集中在上皮细胞基底层及浅层基质。结论:在角膜移植免疫排斥反应中细胞凋亡发挥着重要作用。IL-1ra可通过抑制角膜植片中细胞的凋亡进而抑制角膜移植免疫排斥反应,而延长植片的存活时间。

Effect of IL-1 receptor antagonist on cell apoptosis in rat corneal grafts

AIM: To observe the apoptosis of cells in rat corneal grafts at acute rejection phase and explore the effects of IL-1 receptor antagonist (IL-1ra) on cell apoptosis. METHODS: The penetrating corneal transplantation model was established. Corneal grafting was divided into four groups, namely, normal Wistar rat control group (no grafting, group A), isograft (Wistar rat-->Wistar rat, group B), allograft (Wistar rat-->SD rat) with normal saline treatment (group C) and allograft (Wistar rat-->SD rat) with IL-1ra treatment (group D). Cell apoptosis in corneal grafts was detected by TUNEL staining at 7 d, 10 d and 14 d after transplantation, and an automatic image analyzer was used to analyze the results, which were expressed as positive unit (PU). The changes of cellular ultrastructure in corneal grafts were observed under transmission electron microscope. RESULTS: (1)The average survival time of corneal grafts in C and D groups was (10.38+/-1.85) d and (13.56+/-1.94) d, respectively, with significant difference (P<0.01). (2)As compared with normal and non-rejected corneas, cell apoptosis and necrosis commonly existed in corneal grafts which rejection had occur. (3)In normal corneas, there were merely a very small number apoptotic cells in epithelial laminal, and apoptotic cells were found hardly in stromal laminal and endothelial cell layers. However, sporadic apoptotic cells were found in all layers of corneal grafts in B, C and D groups at 10 d after transplantation, the average PU being of no notably difference (P>0.05). Apoptosis obviously increased in nearby regions of wound and central area of corneal grafts in C and D groups, especially in C group. The apoptotic cells were distributed mainly in basal layer of epithelial cells and stroma of superficial layer. CONCLUSION: Cell apoptosis plays an important role in corneal graft rejection reaction. IL-1ra treatment can prolong the survival time of corneal grafts by means of suppression of cell apoptosis in corneal grafts.