人Stro-1~＋间充质干细胞诱导小鼠皮肤移植免疫耐受的初步研究

Immune Tolerance Induced by Human Stro-1 Positive Mesenchymal Stem Cells in Mouse Skin Graft

本研究探讨人间充质干细胞(MSC)及其Stro-1+MSC亚群对小鼠皮肤移植模型的诱导移植免疫耐受作用。从健康成人骨髓单个核细胞中培养MSC,并筛选Stro-1+MSC。建立小鼠同种异体皮肤移植模型,供体为雌性C57BL/6小鼠,获取皮片,移植给受体雌性BALB/c小鼠。动物分为4组:①Stro-1+MSC组:照射受鼠移植前输注2×106Stro-1+MSC;②MSC组:照射受鼠移植前输注2×106MSC;③照射对照组:受鼠照射后直接进行皮肤移植;④同系对照组:BALB/c小鼠照射后接受同系小鼠皮肤移植。检测项目包括:移植皮片存活时间,HE染色观察移植皮片病理改变,ELISA检测移植前后受鼠血浆转化生长因子β1(TGF-β1)浓度的变化。结果显示:MSC组皮肤移植物存活时间为(12.13±3.34)d,较照射对照组(11.38±1.01)d未见明显延长(P>0.05);Stro-1+MSC组皮肤移植物存活时间为(30.68±5.89)d,较照射对照组及MSC组明显延长(P<0.05),移植皮肤病理检查显示皮片结构清晰。在同系对照组和照射对照组,移植前后受鼠血浆中TGF-β1浓度无显著变化,而在MSC组和Stro-1+MSC组移植后TGF-β1浓度均有显著增高(P<0.05)。结论:Stro-1+MSC较未分选的MSC具有更强的诱导移植免疫耐受的功能,在体内可显著延长小鼠皮片的存活时间,而这种作用似与TGF-β1的表达无关。

This study was aimed to evaluate whether human mesenchymal stem cell（MSC） and the Stro-1 positive subgroup have inducing immune tolerance effect in mouse skin graft model.Human MSC were isolated and cultured from bone marrow-derived mononuclear cells of healthy adults,and Stro-1 positive cells were sorted out.Female C57BL/6 mice and female BALB/c mice were respectively used as donors and recipients in skin allogenic graft model.The recipients were divided randomly into 4 groups：（1） Stro-1＋ MSC group： 2×106 Stro-1＋ MSC were injected into the irradiated recipient mice before skin graft.（2） MSC group： 2×106 MSC were injected into the irradiated recipient mice before skin graft.（3） Irradiation control group： the recipient mice were just irradiated before skin allogenic graft.（4） Congenic control group： the irradiated BALB/c mice received the skin from the congenic mice.The survival time and pathologic changes of skin grafts were observed by macro-and microscopy with HE staining.The transforming growth factor β1（TGF-β1） concentration in plasma of recipient mice was measured by ELISA before and after grafting.The results indicated that the survival time of skin grafts in the MSC group was（12.13±3.34） d,which was not notably longer than the irradiation control group（11.38±1.01） d.The survival time of skin grafts was significantly prolonged in the Stro-1＋ MSC group（30.68±5.89） d,as compared with the irradiation control group and the MSC group,respectively;the pathologic examination of skin grafts showed a clear structure.After grafting,the TGF-β1 concentration in plasma of recipient mice was almost the same as before grafting in the irradiation control group and the congenic control group,but it significantly increased in the MSC group and the Stro-1＋ MSC group.It is concluded that the Stro-1＋ MSC induce greater immune tolerance than the unsorted MSC,and significantly prolong the survival time of skin grafts in vivo,while TGF-β1 does not contribute to the immune tolerance.