人脐血间充质干细胞促进脐血CD34+细胞在NOD/SCID小鼠体内植入的实验研究

目的探讨人脐血间充质干细胞(MSC)联合人脐血CD34+细胞移植,能否促进CD34+细胞在NOD/SCID小鼠体内植入及加速其造血恢复.方法NOD/SCID小鼠于60Co 2.5 Gy照射后24h内由尾静脉输注胎儿脐血CD34+细胞1×105/只(低细胞量移植组)或1×106/只(高细胞量移植组),联合移植组同时输注脐血MSC 1×106/只.动态观察移植后小鼠外周血白细胞、血红蛋白和血小板恢复情况,于移植后第8周用流式细胞术检测存活小鼠骨髓中人CD45+、CD45+CD3+、CD45+CD19+和CD45+CD33+细胞的含量.结果①低细胞量移植时,联合移植组的植入率明显高于单纯移植组,分别为26.02%和16.52%(P＜0.05);高细胞量移植时,联合移植组和单纯移植组的植入率相近,分别为43.71%和39.23%(P＞0.05).②高细胞量联合移植组和单纯移植组的存活率分别为80%和70%;低细胞量联合移植组和单纯移植组的存活率分别为70%和50%.③无论高细胞量还是低细胞量组,联合移植小鼠白细胞、血红蛋白和血小板的恢复明显早于单纯移植组.④移植8周后,小鼠骨髓中人CD45+CD19+、CD45+CD33+细胞含量在低细胞量移植时,联合移植组高于单纯移植组;但在高细胞量移植时,两组之间差异无统计学意义.CD45+CD41a+细胞的含量无论在低细胞量和高细胞量移植时,联合移植组均高于单纯移植组.各组小鼠骨髓中CD45+CD3+细胞的含量均较少,且各组之间差异无统计学意义.结论①低细胞量移植时,人脐血MSC联合移植可提高人脐血CD34+细胞在小鼠体内的植入率.②人脐血MSC与人脐血CD34+细胞联合移植,加速NOD/SCID小鼠各系造血恢复,提高移植小鼠存活率.③MSC联合移植可促进人脐血CD34+细胞在NOD/SCID小鼠体内向粒系、B淋巴系和巨核系定向分化.

Mesenchymal stem cells from human cord blood promote engraftment of human umbilical cord blood-derived CD34+cells in NOD/SCID mice

OBJECTIVE: To explore whether the co-transplantation of mesenchymal stem cells (MSC) from human umbilical cord blood (UCB) with UCB-derived CD34(+) cells in NOD/SCID mice could promote engraftment and accelerate hematopoiesis recovery. METHODS: After sublethal irradiated ((60)Co 2.5 Gy), NOD/SCID mice received within 24 hours UCB CD34(+) cells (1 x 10(5) per mouse for low dosage group or 1 x 10(6) per mouse for high dosage group) with or without human UCB-derived MSC (1 x 10(6) per mouse) transplantation by lateral tail vein injection. Peripheral blood cells of transplanted mice were measured for white blood cell count, hemoglobin and platelet count at 10th, 20th, 30th, 40th and 56th day. At the end of 8th week after transplantation, all the alive mice were sacrificed and human derived CD45(+), CD45(+)CD3(+), CD45(+)CD19(+), CD45(+)CD33(+) cells in the bone marrow (BM) were assayed by flow cytometry. RESULTS: (1) In the low dosage group, co-transplantation of MSC significantly raised the engraftment rate (26.02% vs 16.52%) (P < 0.05). (2) The survival rate in high dosage group was 80% for co-transplantation mice and 70% for CD34(+) cells alone transplantation mice. The survival rate in low dosage group was 70% for co-transplantation mice and 50% in CD34(+) cells transplantation mice. (3) In both dosages groups co-transplantation accelerated the hematopoiesis recovery. (4) At the end of 8 weeks after transplantation, in low dosage group, CD45(+)CD33(+) and CD45(+)CD19(+) cells were more in co-transplantation mice than in CD34(+) cells alone transplantation mice, but in high dosage group, the percentage of these two kinds of cells had no difference. In both dosage groups the percentage of CD45(+)CD41a(+) cells were higher in co-transplantation than in transplantation alone mice. CD45(+)CD3(+) cells were low in all groups. CONCLUSIONS: (1) In low dosage transplantation, human UCB MSC could promote human CD34(+) cells engraftment in transplanted mice. (2) Co-transplantation of human UCB MSC and human UCB CD34(+) cells could significantly promote the hematopoiesis reconstitution and improve the survival rate of NOD/SCID mice. (3) MSC could promote human UCB CD34(+) cells to differentiated into B-lymphocytes, granulocyte and megakaryocyte in vivo.