脐血间充质干细胞表达的IDO对异基因淋巴细胞的增殖及再生障碍性贫血小鼠造血恢复的影响

Effect of UCB-MSCs IDO Expression on Allogeneic Lymphocyte Proliferation and Hematopoietic Functions in Aplastic Anemia Mice

目的探讨脐带血间充质干细胞(UCB-MSCs)发挥免疫调节作用机制及对再生障碍性贫血小鼠的治疗效应。方法采集足月胎儿脐带血,采用羟乙基淀粉沉降+淋巴细胞分离两步法分离培养UCB-MSCs。观察细胞形态,流式细胞术检测细胞表面标志物,成骨、成脂诱导鉴定分化潜能。研究UCB-MSCs表达吲哚胺2,3-过氧化酶(IDO)的情况。建立UCB-MSCs与异基因淋巴细胞共培养体系,探讨其发挥免疫调节作用的机制;同时构建免疫介导再生障碍性贫血小鼠模型,观察其对再障造血恢复的影响。结果 UCB-MSCs为成纤维样细胞,贴壁生长。流式细胞仪检测结果表明,其不表达造血标志CD34,高表达CD44、CD73,体外成功诱导成骨与成脂分化。经γ干扰素(IFN-γ)诱导表达IDO活性,对异基因淋巴细胞的增殖可能发挥免疫抑制作用。MSCs输注再生障碍性贫血小鼠模型,可减轻小鼠骨髓造血衰竭程度。结论 UCB-MSCs在体外成功分离培养,并具有间充质干细胞生物学特性;MSCs可能通过IDO途径发挥免疫负调控作用。UCB-MSCs的IDO表达对于免疫介导再障小鼠模型的骨髓造血恢复具有改善作用。

Objective To examine the activity of indoleamine 2,3-dioperoxidase （IDO） in umbilical cord blood-mesenchymal stem （UCB-MSCs） isolated from human umbilical cord blood and the immune regulatory role of UCB-MSCs in the treatment of aplastic anemia mice. Methods The umbdlcal cord blood was collected from full-term deliveries. UCB-MSCs were isolated and cultured by using the hydroxyethyl starch sedimentation＋lymphocyte isolation method. The morphology of UCB-MSCs was observed by light microscopy and the surface markers analyzed by flow cytometry. The differentiation potential of UCB- MSCs was evaluated by inducing osteogenic and adipogenic differentiation. The IDO expression in allogeneic lymphocyte cultures was detected. Immune-mediated aplastic anemia models were established in mice. UCB-MSCs were infused through the vena caudalis. The effect of UCB-MSCs in aplastic anemia mice was observed. Results UCB-MSCs were fibroblast-like cells attached to the culture dish. Immunophenotype analysis showed that UCB-MSCs were positive for CD44 （94.36%） and CD73 （92.48 %）,but failed to express hematopoietic lineage marker CD34. They could undergo adipocyte and osteocyte differentiation. UCB-MSCs induced by IFN-γ could express IDO, and they could promote the hematogenesis recovery of aplastic anemia mice. Conclusion UCB-MSCs were successfully isolated and cultured in vitro. The cells had the biological characteristics of mesenchymal stem cells. UCB-MSCs induced by IFN-γ could express IDO to exert the immunosuppressive effect. The IDO ex- pression could reduce bone marrow failure-of aplastic anemia mice.