骨髓间充质干细胞移植途径对胰岛移植物免疫排斥反应的影响

Effects of different routes of mesenchymal stem cells transplantation on islet graft rejection

目的:探讨骨髓间充质干细胞(MSC)与胰岛共移植对诱导胰岛移植物免疫耐受的作用,并比较MSC不同途径移植的效果。方法:SD大鼠和Lewis大鼠分别作为供、受体。取SD大鼠股骨,贴壁培养法分离和扩增MSC,胶原酶V分离胰岛。应用链脲佐菌素制备Lewis大鼠糖尿病模型后,将其随机均分为A组(将BrdU标记的MSC与胰岛经门静脉混合输入),B组(将胰岛经门静脉输入,BrdU标记的MSC经尾静脉输入),C组(胰岛经门静脉输入,联合应用环孢素A)和D组(单纯胰岛门静脉移植)。观察各组术后血糖变化,比较各组胰岛移植物存活时间。术后第7天切取各组部分存活大鼠肝脏、胸腺、脾脏行免疫组化染色观察MSC归巢位置。结果:A,B两组大鼠术后正常血糖维持时间最长,C组次之,D组最短;各组胰岛存活时间A组为(12.1±2.3)d,B组为(8.6±1.4)d,C组为(13.2±1.9)d,D组为(2.2±0.6)d;MSC归巢部位观察显示,A组BrdU阳性的MSC主要分布于肝脏,并在植入胰岛周围形成"类微囊化效应",B组BrdU阳性的MSC主要分布于胸腺、脾脏。结论:MSC与胰岛共移植能诱导胰岛移植物免疫耐受,且MSC和胰岛混合经门静脉移植效果优于胰岛门静脉移植联合MSC外周静脉移植。

Objective： To investigate the effect of co-transplantation of islet and mesenchymal stem cells（MSCs） to induce immune tolerance on islet graft,and to compare the efficacies of MSCs via different delivery routes. Methods： SD and Lewis rats were used as donor and recipient,respectively.MSCs were isolated from the femur of the SD rats with adherence culture method and then expanded in vitro.Islets were also isolated from the donor pancreas by collagenase-V digestion.Forty recipient Lewis rats with streptozotocin induced diabetes were equally randomized into group A（islets combined with BrdU-labeled MSCs were transplanted via portal vein）,group B（islets were transplanted through portal vein and BrdU-labeled MSC were infused via tail vein）,group C（islets transplantation through portal vein combined with cyclosporine administration） and group D（islets transplanted via portal vein without any other intervention）.Blood glucose levels of the recipient rats were observed after transplantation and the survival times of islet grafts in each group were compared.On the 7th day after transplantation,the samples of liver,thymus gland and spleen were taken from some of the living donors to observe homing sites of MSCs. Results： Both group A and B had the longest maintenance times of normal blood glucose level,followed by group C,and that of group D was the shortest.The survival time of islet graft in group A was（12.1±2.3） d,group B was（8.6±1.4） d,group C was（13.2±1.9） d and group D was（2.2±0.6） d,respectively.MSCs homing observation showed that in group A,the BrdU-positive MSCs were mainly located in the liver,and some of them formed the ＂microencapsulation＂ that enclosed islet grafts,while MSCs were mainly observed in the thymus gland and spleen in group B. Conclusion： Co-transplantation of islets and MSCs can promote immune tolerance for islet grafts,and MSCs delivery through portal vein has better efficacy than that observed through peripheral vein.