供者骨髓基质干细胞输注延长大鼠移植心存活时间的探讨

目的 探讨供者骨髓基质干细胞(MSC)输注在大鼠同种心脏移植术后的免疫调节及延长移植心存活时间的作用.方法 供者为近交系Wistar大鼠,受者为Fisher 344大鼠.处死供者后抽取其股骨和胫骨中骨髓,分离和培养MSC.通过混合淋巴细胞试验观察不同密度的MSC对异源性T淋巴细胞增殖反应的抑制作用.建立大鼠异位心脏移植模型,根据处理方式的不同,将受者分为MSC输注组和对照组,每组8只.Msc输注组:将含有2×106个MSC的林格氏液分别于术前1周、术中及术后连续3 d经尾静脉注入受者体内;对照组:用与MSC输注组相同的方法在相同时间点注入不含MSC的林格氏液.术后第5天,采用实时逆转录聚合酶链反应检测移植心组织中细胞因子的表达情况.结果 供者MSC可明显抑制异源性T淋巴细胞的增殖反应,且MsC密度越高抑制作用越强.MSC输注组Th1类细胞因子白细胞介素(IL)-1β和γ干扰素的表达要显著低于对照组;MSC输注组Th2类细胞冈子IL-4和IL-10呈高表达,而对照组基本不表达.MSC输注组移植心平均存活时间为(12.4±5.3)d,与对照组的(6.4±2.0)d比较,差异有统计学意义(P＜0.01).结论 输注供者MSC可通过改变Th1/Th2类细胞因子的平衡向Th2偏移诱导受者产生免疫调节作用,从而延长移植心存活时间.

Prolongation of allograft survival by donor mesenchymal stem cells infusion in rat heart transplantation

Objective To investigate the immunomodulatory effect of mesenchymal stem cells (MSCs) and their role in prolonging allograft survival in rat heart transplantation. Methods Inbred Wistar rats were used as donors, and Fisher 344 as recipients. MSC were isolated from femur and tibia bone marrow of donors and cultured in vitro. Mixed lymphocyte reaction assays were performed to assess the immunosuppressive effects of different concentrations of MSC on allogeneic T cell proliferation. Cardiac allograft model was established and according to different intervention measures recipients were divided into two groups (MSC treatment group and control group) (n=8 in each group). In MSC treatment group, recipients were infused with 2×106 MSC via the tail vein at designated intervals (one week before operation, during operation and consecutive three days postoperation), while in control group, the recipients were treated with Ringer's solution at the same interval& At day 5 posttransplantation real-time PCR was used to detect the changes in the expression of Thl and Th2 cytokine genes in transplanted hearts. Results In vitro allogeneic T cell response was greatly suppressed by MSC in a dose-dependent manner. Real-time PCR revealed that IL-1β,IFN-γ, IL-4 and IL-10 were expressed in MSC treatment group, while IL-4 and IL-10 were not expressed in control group but with significantly higher expression of IL-1β and IFN-γ. As compared with control group, survival of MSC-treated allografts was markedly prolonged as compared with control group (mean survivaldays: 12.4±5.3 vs 6.4±2.0, P＜0.05). Conclusion Intravenous adrninistmtion of MSC can prolong the survival of transplanted heart possibly by induction of allograft tolerance through changing Th1/Th2 balance.