过继性回输Treg对小鼠同种胰岛移植物免疫排斥反应的影响

Effect of adoptive reinfusion of Treg on immune rejection of islet allografts in mice

目的探讨过继性回输调节性T细胞(Treg)对同种胰岛移植术后胰岛功能恢复及移植物存活时间的影响。方法以C57BL/6小鼠为受体建立糖尿病模型,以Balb/c小鼠为供体进行肾包膜下同种小鼠胰岛移植。根据处理方法不同将受体小鼠分为3组:Treg实验组(Treg组,术前1d经尾静脉注射1×10^6个Treg细胞)、阳性对照组[西罗莫司(SRL)组,术前1d开始给予300μg/(kg·d)SRL灌胃]和空白对照组(对照组,术前1d开始每日给予等体积生理盐水灌胃),每组3只。采用酶联免疫吸附试验(ELISA)检测小鼠术后14d内血糖、C肽变化情况;通过活体成像技术动态监测小鼠移植物术后14d内存活情况。结果与移植术前比较,术后3d各组小鼠血糖水平均显著降低(均为P<0.001)。术后1d各组小鼠C肽水平均出现不同程度的爆发性回升,术后3d各组小鼠C肽水平较术前明显升高(均为P<0.001)。在术后14d观察期结束时,与对照组比较,SRL组与Treg组C肽水平仍相对较高[(427±50)、(833±57)pmol/L];而两组的血糖水平[(14.5±0.5)、12.1±0.6)mmol/L]均显著低于对照组(均为P<0.001)。与SRL组比较,Treg组C肽爆发性释放量更低,下降趋势明显更加平缓,观察期结束时C肽水平较高(均为P<0.001)。术后14d对照组的移植物几乎完全凋亡,SRL组有>50%的移植物存活,Treg组有>80%的移植物存活。结论过继性回输Treg能有效保护胰岛移植物,延长移植物存活时间,维持移植小鼠血糖以及C肽的正常水平。

Objective To investigate the effects of adoptive reinfusion of regulatory T cell (Treg) on the recovery of islet function and graft survival time after islet allograft transplantation. Methods The diabetic model was established using C57BL/6 mice as recipients, and Balb/c mice were chosen as donors for islet allografts transplantation beneath the renal capsule. The recipient mice were divided into 3 groups and 3 mice in each group according to different processing methods: Treg experiment group (Treg group, 1×10^6 Treg cells were injected via tail vein at 1 d before operation), positive control group [sirolimus (SRL) group, SRL at a dose of 300 μg( / kg·d) was intragastrically given every day from 1 d before operation] and blank control group (control group, an equivalent volume of normal saline was intragastrically given every day from 1 d before operation). Enzyme-linked immune absorbent assay (ELISA) was used to detect the changes of blood glucose and C-peptide in mice within 14 days after transplantation. In vivo imaging technique was used to dynamically monitor the survival of mice within 14 days after transplantation. Results In each group, the blood glucose levels at postoperative 3 d were significantly decreased compared with those before transplantation (all P<0.001). At postoperative 1 d, the C-peptide levels showed an explosive rise to varying degree in each group. At postoperative 3 d, the C-peptide levels in each group were significantly higher than that before operation (all P<0.001). At the end of the observation period at 14 d after operation, the C-peptide levels in the SRL and Treg groups were (427±50) pmol/L and (833±57) pmol/L, relatively higher than that in the control group. But the blood glucose levels were (14.5±0.5) mmol/L and (12.1±0.6) mmol/L, significantly lower than that in the control group (all P<0.001). Compared with the SRL group, the explosive release amount of C-peptide was significantly lower, the declining trend was more remarkably stable, and the C-peptide level was considerably higher in the Treg group at the end of the observation period (all P<0.001). At postoperative 14 d, the grafts were almost completely apoptotic in the control group, over 50% of the grafts survived in the SRL group, and over 80% of the grafts survived in the Treg group. Conclusions Adoptive reinfusion of Treg cells can effectively protect islet grafts, prolong the survival time of grafts, and maintain the normal levels of blood glucose and C-peptide in the recipient mice.