白细胞介素2-绿脓杆菌外毒素抑制小鼠角膜移植后的排斥反应

目的 观察白细胞介素2-绿脓杆菌外毒素(IL-2-PE40)对小鼠角膜移植排斥反应的抑制作用.方法 以C57BL/6小鼠为供者,Balb/c小鼠为受者,制备小鼠同种异体穿透性角膜移植模型,治疗组受者于手术当天起腹腔注射IL-2-PE40,用量为0.6μg/g,每12 h 1次,直至排斥反应发生;对照组相应时间点腹腔注射等体积生理盐水.术后每周在裂隙灯下观察移植角膜2次,根据Hori等的分级标准,对移植角膜混浊和新生血管进行分级,判断排斥反应发生情况,发生排斥反应时判定为移植角膜存活终止;并在术后第10、15、25、35天分别取术眼,行组织学观察,同时收集外周血,测定T淋巴细胞亚群及T淋巴细胞集落形成数.结果 治疗组与对照组移植角膜存活时间分别为(30.2±2.9)d和(15.1±2.1)d,对照组于术后第15天出现排斥反应;术后对照组CD4~+细胞开始升高,于第15天升高最为明显,达(63.9±4.0)%,随后下降,而治疗组CD4~+细胞仅轻微上升,第15天为(42.6±4.0)%,明显低于对照组(P<0.01);术后2个组CD8~+细胞变化不大;术后对照组T淋巴细胞集落形成数呈先升后降趋势,第15天上升最为明显,为(296±17)个,随后下降,而治疗组的变化不明显,第15天为(201±16)个,明显低于对照组(P<0.01).结论 IL-2-PE40可推迟角膜移植排斥反应的发生时间;能明显减少外周血中辅助性T淋巴细胞的作用,并能减弱小鼠外周血T淋巴细胞集落形成能力.

Inhibitory effects of cytotoxin IL-2-PE40 on corneal allograft rejection

Objective To examine the inhibitory effect of IL-2-PE40 on the mouse corneal allograft rejection. Methods A mouse corneal graft model was set up by using C57BL/6 mice as donors and Balb/c mice as recipients. In the treatment group, IL-2-PE40 (0.6 μg/g body weight) was intraperitoneally injected from the day of surgery every 12 h until rejection happened. In the control group, the equal volume of PS was injected intraperitoneally at the corresponding time points. The transplanted cornea was observed under slit-lamp twice a week and the transplanted corneal opacity and neovascularization were rated according to Horis grading standards. It led to the determination of rejection response. The survival of transplanted cornea was regarded to be stopped when the rejection occurred. The operated eyes were observed historically on the 10th, 15th, 25th and 35th day after the surgery, and the peripheral blood was collected for measurement of T cell subgroups and T lymphocyte colonies. Results The survival time of cornea in the treatment and control groups was (30.2±2.9) days and (15.1±2.1) days respectively. In the control group, rejection occurred on the 15th day after the surgery, CD4~+ cells started rise right after the surgery and increased most obviously on the 15th day (63.9±4.0)%] and decreased afterwards. CD4~+ cells in the treatment group were increased slightly (42.6±4.0)%] on the 15th day. The number of CD4~+ cells in the treatment group was obviously less than in the control group (P<0.01). No significant changes in CD8~+ cells were observed in both groups. The number of T lymphocyte colonies in the control group was increased at the beginning and dropped then. No obvious change was found in the treatment group. The number of T lymphocyte colonies in the treatment group was significantly less than in the control group (P＜0.01). Conclusion IL-2-PE40 is a highly specific immunosuppressive agent. It can delay the development of corneal graft rejection and reduce the percentage of T-helper cells significantly. It also works to weaken the forming capacity of the peripheral T lymphocyte colonies.