小鼠骨髓间充质干细胞减轻胰岛移植物排斥反应的作用

The effect of mouse bone marrow-derived mesenchymal stem cells on islet graft rejection

目的 探讨同种异基因小鼠骨髓间充质干细胞（MSC）与胰岛联合移植对胰岛移植物的免疫调节作用.方法 将18只糖尿病模型小鼠随机分成3组：（1）糖尿病组,不进行任何移植;（2）胰岛移植组,在无菌操作下将10μl纯化后的200个胰岛移植于受者的左肾包膜下;（3）胰岛＋MSC移植组,除与胰岛移植组进行相同的移植外,还在胰岛移植前3、2、0d经受者尾静脉分别注射1×106个MSC.移植后,连续监测非空腹血糖至第30 d;第14和28 d对移植部位的左肾进行组织病理学观察;采集外周血进行免疫荧光染色,流式细胞术分析TH1/TH2、Tc1/Tc2细胞的比值、初始和记忆T淋巴细胞的变化、以及骨髓来源的树突状细胞（DC）成熟度和功能的变化.结果 与胰岛移植组比较,胰岛＋MSC移植组血糖明显降低,移植部位炎症细胞浸润明显减轻,移植物的存活时间延长;TH1和Tc1细胞明显下降,TH2和Tc2细胞升高,TH1/TH2和Tc1/Tc2细胞比值显著下降;初始T淋巴细胞和记忆T淋巴细胞下调;DC成熟度降低,分泌白细胞介素12（IL-12）的能力下降.结论 MSC与胰岛联合移植可通过对T淋巴细胞和树突状细胞的免疫调节作用,减轻胰岛移植物的排斥反应,从而延长移植胰岛的存活时间.

Objective To investigate the immune regulatory effects of allogeneic bone marrowderived mesenchyrnal stem cells （MSCs） co-transplanted with islets. Methods The 18 diabetic mice were randomly divided into 3 groups： Diabetic group, without any transplantation; Islet transplantation group, in a sterile operation, with 10 μl purified islets （about 200 islets）transplantation to the left renal subcapsule of recipients; Islet ＋ MSCs transplantation group, in addition to transplantation as the former group, 1 × 106 MSCs were given to the recipients via tail vein on 3, 2 and 0 days before islet transplantation. Blood glucose in recipient mice was monitored for 30consecutive days after transplantation. Pathological characteristics of left kidney were analyzed on the day 14 and 28 after transplantation. Th1/Th2, Tc1/Tc2, naive and memory T cells from peripheral blood and bone marrow-derived dendritic cells （DCs） were analyzed by multi-color flow cytometry.Results As compared with the islet transplantation group, blood glucose was significantly reduced,inflammatory cell infiltration decreased in the place of transplantation, graft survival prolonged, the number of Th1 and Tc1 cells was obviously reduced, the number of Th2 and Tc2 cells increased, the ratio of Th1/Th2 and Tc1/Tc2 cells was significantly decreased, the naive and memory T cells were significantly inhibited, the maturity of DCs and the secretion of interleukin-12 decreased in the islet transplantation group. Conclusion Through the immunomodulation on T-cell and DCs function,MSCs can alleviate graft verse host disease and prolong allograft survival.