成人骨髓间充质干细胞对造血干细胞体外增殖的影响

目的研究骨髓间充质干细胞（MSC）对脐带血（CB）CD34^＋细胞体外增殖和造血重建能力的影响。方法取人骨髓单个核细胞贴壁培养．梭形细胞完全融合后传代，用流式细胞仪检测免疫表型；将CBCD34^＋细胞接种到MSC或其他培养液中．比较不同培养条件对造血干细胞扩增能力、集落形成能力及黏附分子表达的影响。结果在加入IL-3的培养体系中．在MSC和细胞因子作用下，CD34^＋细胞扩增7d和14d后，有核细胞（NC）、CD34^＋细胞和CDl33^＋细胞数，实验组均显著多于对照组。CD34＋细胞在未加入IL-3的培养体系中培养8d后，实验组NC、CD34^＋细胞、CD34^＋CD38-细胞和造血祖细胞集落扩增倍数均显著高于对照组。扩增后CD34^＋细胞的ALCAM、VLA-α4、VLA-α5、VLA-β1、HCAM、PECAM和LFA-1表达较扩增前无显著变化。结论MSC可为造血干细胞（HSC）体外扩增提供适宜的微环境，有助于CD34^＋细胞体外增殖并抑制HSC分化，保持其造血重建潜能和归巢能力。

The effect of adult bone mrrow mesenchymal stem cells on ex vivo hematopoietic stem cells

Objective To explore beneficial effect of human bone marrow-derived mesenchymal stem cells （MSC） on ex vivo expansion of cord blood（CB） hematopoietie stem eells（HSC）. Methods The MSC were obtained from human bone marrow aspirates and their phenotype were identified by flow eytometry. CB CD34^＋ cells were expanded on MSC layer or MSC-free culture systems and the effect of MSC on expansion potential and expression of adherent molecules on CB CD34^＋ cells were investigated. Results After 7 days of culture with IL-3 and other eytokins, expansion of CD34^＋ cells on MSC feeder layer resulted in a significantly higher numbers of nucleated cells（NC ）, CD34^＋ cells and CD 133^＋ cells than that cultured in the presence of eytokines alone. After culturing on MSC layer without IL-3 for 8 days,increasing in the absolute numbers of NC,CD34^＋ ,CD34^＋ CD38-cells and CFU-Cs were significantly higher than that cultured in the presence of eytokines alone. The expression of ALCAM, VLA-α4, VLA-α5, VLA-β1, HCAM, PECAM and LFA-1 on CD34^＋ cells remained unaffected. Conclusion The addition of MSC as a feeder layer provides improves conditions for expansion of HSC and may inhibit their differentiation and remain their homing ability.