移植途径对骨髓间充质干细胞调节小鼠心脏移植排斥反应的影响

目的 探讨不同途径注射骨髓间充质干细胞（BMSCs）对调节小鼠心脏移植排斥反应的影响。方法 BALB/c和C57小鼠分别作为供体和受体，建立颈部心脏移植模型，随机分为4组，每组12只，A组在移植成功后立即经移植心脏升主动脉注射C57来源绿色荧光BMSCs悬液30 μL（含1×106细胞），B组同样时间点经移植心脏右心室腔内注射相同数量细胞，C组同样时间点移植心脏心肌内注射相同数量细胞，D组为空白对照组。移植后第7天各组处死4只小鼠，切取移植心脏，荧光显微镜下观察绿色荧光细胞的存活情况，HE染色观察移植心脏的病理学改变，流式细胞学检测移植物浸润白细胞中巨噬细胞的比例，其余8只小鼠用来观察移植心脏的存活时间。结果 术后第7天，仅A组移植心脏内可见绿色荧光细胞，病理学检测发现A组排斥反应受到明显抑制，心肌间质内细胞浸润明显减少，局灶性的心肌细胞损害，B组和C组移植心脏间质内可见多灶性淋巴细胞浸润并伴有心肌细胞变性坏死，而D组小鼠心脏见满视野大量白细胞浸润，心肌结构消失，心肌坏死。流式细胞学检测发现A组移植心脏内巨噬细胞的比例明显高于其他3组，A组的心脏存活时间明显长于其他3组。结论 BMSCs能减轻心脏移植排斥反应，动脉途径注射优于静脉和心肌局部注射途径，其机制可能与骨髓间充质干细胞在移植心脏内存活时间以及巨噬细胞比例增加有关。

The effect of cell administration route of bone marrow mesenchymal stem cells on the regulating immune rejection against heart allograft in mice

Objective To investigate the effect of cell administration route of bone marrow mesenchymal stem cells onregulating immune rejection against heart allograft. Methods Donor hearts from BALB / c mice were heterotopically transplanted into the neck of C57 mice. The recipient animals were randomly divided into 4 groups with 12 animals in each group. In group A, 30 μL cell suspension containing 1×106 eGFP-BMSCs was injected into the animals through heart graft ascending aorta immediately after heart transplant procedure. In group B, the same dose of cell suspension was injected into animals through heart graft right ventricle cavity at the same time point. In group C, the same dose of cell suspension was injected into the heart muscle directly. Group D was control group and no treatment was received. Four mice were sacrificed in each group at post-operative day 7, and the heart grafts were harvested. Green fluorescence cells were detected undermicroscope and the heart graft histology was evaluated by HE staining. The proportion of macrophages in the heart graft infiltrating leukocytes was measured using flow cytometry. The remaining 8 mice were monitored for heart graft survival.Results At day 7 after transplantation, the eGFP+ cells were only detected in the heart graft of group A. The pathological examination found that the immune rejection was inhibited in group A with less interstitial infiltration and focal heart muscle damage. In group B and C, multifocal lymphocytic infiltration with myocardial cell degeneration and necrosis was observed in the interstitium of transplanted heart. In group D, large number of white blood cells infiltrated in all the graft, and normal myocardial structure disappeared. Flow cytometry analysis showed that highest macrophages cell proportion was found in the graft infiltrating leukocytes in group A compared to those of other groups. Cardiac survival time was significantly longer in group A than that of other groups. Conclusion BMSCs can alleviate cardiac allograft rejection. Intra-arterial injection is the best compared to intravenous and intra-myocardial injection route. The related mechanism may be the longer BMSCs survival and the higher macrophages infiltration in heart graft.