人骨髓间质干细胞向造血细胞分化潜能的实验研究

目的:在体研究人骨髓间质干细胞(hBMMSCs)向造血细胞分化的潜能。方法:将hBMMSCs经尾静脉注射给环磷酰胺处理的严重联合免疫缺陷(SCID)小鼠,利用流式激活细胞分析系统(FACS)检测hBMMSCs输注后存活35d的SCID小鼠外周血、骨髓和脾脏中人源性造血细胞的表型和水平。结果:hBMMSCs输注组外周血(PB)、骨髓(BM)和脾脏(spleen)中可检测到人CD45⁺/H-2D^d-、CD34⁺/H-2D^d-细胞,而对照组PB、BM和脾脏均未检测到上述表型的人造血细胞。结论:hBMMSCs具有向造血细胞分化的潜能。

Studies on differentiation potential of human bone marrow mesenchymal stem cells into hematopoietic cells in vivo

AIM:To investigate the differentiation potential of human bone marrow mesenchymal stem cells (hBMMSCs) into hematopoietic cells in vivo. METHODS:hBMMSCs prepared from the bone marrow-aspirate sample obtained from healthy human donors were culture-expanded in vitro with 5-8 passages. hBMMSCs(P5-8, 4.8×10⁵ cells/mouse) were injected into the severe combined immuodeficiency (SCID) mice treated by cyclophosphamide(CPA) and various tissues were analyzed at 35 days post-transplant for the presence of differentiated human cells.RESULTS:hBMMSCs(P5-8) viability, which was determined by typan blue staining at the end of the harvest and before infusion, was greater than 95% in every infusate at both time points. Cells characterized by flow cytometry using human MSC-specific monoclonal antibodies were uniformly positive for CD29, CD44, CD90, CD105, CD106, CD166 and negative for CD11a, CD14, CD34, CD38, CD45, CD80, CD86 which are common on cells of the hematopoietic lineages. Analysis of PB demonstrated that 5 of 6 hBMMSCs transplanted SCID mice had low level of circulating human CD45⁺/ H-2D^d- cells(range from 0.17% to 0.36%)and CD34⁺/ H-2D^d- cells(range from 0.10% to 0.50%). Analysis of BM for the presence of hematopoietic chimerism demonstrated human CD45⁺/ H-2D^d- cells and CD34⁺/ H-2D^d- cells in the marrow of 4 out of 6 hBMMSCs transplanted SCID mice (0.10%-0.19% and 0.03%-0.52%, respectively). Human hematopoietic cells with these same phenotype were also detected in the spleen 4 of the hBMMSCs transplanted SCID mice (range from 0.19% to 1.65% ,from 0.20% to 0.26%, respectively). No human hematopoietic cell was seen either in the PB, BM or spleen of all control animals.CONCLUSION:hBMMSCs have the ability to differentiate into blood cells of multiple lineages, including CD34⁺ hematopoietic stem cells/progenitor cells (HSC/HPC).