不同时相移植人骨髓间充质干细胞对人脐血CD34^+细胞植入NOD/SCID小鼠的影响

Hematopoietic Reconstitution by Co-transplantation of Human BM-MSCs and UCB CD34^+ Cells at Various Time in NOD/SCID Mice

为了观察不同时相移植人骨髓间充质干细胞(MSC)对脐血(UCB)CD34+细胞移植的NOD/SCID小鼠造血重建的影响,明确最佳的移植时机,将体外培养扩增的人骨髓MSC分别于c细胞移植同时、移植前48小时及移植后48小时输入经60Coγ射线照射的NOD/SCID小鼠,观察共移植后42天内小鼠外周血白细胞和血小板变化,并于移植后42天处死小鼠,用FACS检测外周血、骨髓和脾脏人源细胞含量。结果表明:(1)MSC和UCB CD34+细胞同时输注可明显降低外周血白细胞和血小板下降幅度,缩短白细胞和血小板恢复时间;二者不同时输注均不降低白细胞和血小板下降幅度,且输注UCB CD34+细胞后48小时输注MSC时外周血血小板恢复时间明显晚于同时输注者。(2)与单纯UCB CD34+细胞移植相比较,不同时相输注MSC均可促进UCB CD34+细胞的植入,三个共输注组间促进骨髓各系造血植入效应无明显差异。结论:人骨髓MSC与UCB CD34+细胞共移植时,以同时移植效果最佳,此结果为MSC的临床应用提供了实验依据。

To investigate the effect of co-transplantation of bone marrow derived MSCs and UCB CD34^＋ cells at different time points on hematopoietic reconstitution, all NOD/SCID mice were sublethally exposed to irradiation of ^60Co γ ray and transplanted with UCB CD34^＋ with or without MSCs （3 mice per group）. Animals were divided into HSC group and MSC ＋ HSC group （M ＋ H group）. In HSC group, 1 × 10^6 UCB CD34^＋ cells for each mouse were infused within 4 - 6 hours after irradiation; the M ＋ H group again was divided into 3 subgroups according to infusion sequence of MSCs and HSCs. （A） M ＋ H simultaneously infused group： MSCs and UCB CD34^＋ cells were infused simultaneously; （B）M ＋48H group： MSCs were infused within 4 -6 hours after irradiation, while UCB CD34^＋ cells were infused at 48 hours after irradiation; （C）H ＋48M group： UCB CD34^＋ cells were infused within 4 -6 hours after irradiation, while MSCs were infused at 48 hours after irradiation. In 3 subgroups infused amounts of MSCs and UCB CD34 ^＋ cells all were 1 × 10^6 cells. From the 3rd day after transplantation, 20 μl peripheral blood was collected from the retroorbital plexus of mice every week until 42th day after transplantation. 42 days after transplantation, mice were sacrificed, and the percentages of human CD45, CD34, CD19 and CD1 lb in bone marrow, peripheral blood and spleen were detected by FACS. The results showed that （ 1 ） Co-transplantation of MSCs and UCB CD34^＋ cells simutaneously （ M ＋ H group） can mitigate the decrease of WBC and platelet levels （p 〈0.01 ） in peripheral blood, and accelated the hemato- poietic recovery. While co-transplantating MSCs and UCB CD34^＋ cells at different time points （M ＋48H or H ＋48M）, the similar effect was not observed （p 〉0.05）. As far as platelets was concerned, the recovery of platelets in M ＋48H group was lagged behind that in M ＋ H group（p 〈0.01 ）. （2） Co-transplantation of MSCs at different time points enhanced the engraftment of hematopoietic cells （p 〈 0.05 or p 〈 0.01 ）, compared with transplantation of CD34^＋ cells alone. The effect of engraftment enhancement was not lineage restriction （p 〉0.05）. It is concluded that the ideal trans- plantation effect is achieved when MSCs and UCB CD34^＋ cells were co-transplanted at the same time, these study results provide experimental basis for clinical application of MSCs.