Objective: To observe the dynamic changes of hematopoietic reconstitution and multiple lineages differentiation at early phase after transplantation.
Methods: Whole bone marrow mononuclear cells (wBMMNC, 5×106) and enriched c-Kit+ hematopoietic stem/progenitor cells (HSPC, 3×105) from the BM of B6-Ly5.1 mice were transplanted into lethally irradiated B6-Ly5.2 mice, the frequencies and absolute numbers of donor-derived cells (including LKS- and LKS+) were detected by flow cytometry. The multiple lineages differentiation of donor-derived cells was also monitored by flow cytometry. The homing and early phase proliferations of donor-derived cells were observed by two-photon microscope.
Results: The donor-derived cells started to proliferation from 5-7 days after transplantation and reached the peak value at 2-3 weeks after wBMMNC transplantation. The donor-derived cells proliferated from 1-2 weeks and maintained until 4 weeks after c-kit+HSPC transplantation. At 1 week after transplantation, the donor-derived cells mainly differentiated into myeloid cells with a few lymphoid cells production (B cells) but the production of T cells was not observed at most in wBMMNC transplanted group, while myeloid cells occupied the majority of donor-derived cells at 2-4 weeks; donor-derived cells almost totally differentiated into myeloid cells at 1-3 weeks after transplantation in c-Kit+ transplanted group and donor-derived B cells appeared at 4 weeks. The absolute number of donor-derived LKS- and LKS+ cells in the BM of c-Kit+ transplanted group were much higher than that of wBMMNC group (P＜0.001) at 2 weeks respectively. The clustering proliferation of cKit+ cells at 4-5 days after transplantation was observed by two photon microscope.
Conclusion: The dynamical rate of proliferation and reconstitution of donor-derived cells are much earlier and quicker in c-Kit+ group than those of wBMMNC group. c-Kit+ cells mainly differentiate into myeloid cells within 1-3 weeks and the lymphoid cell differentiation starts at 4 weeks after transplantation. The immediate proliferation and differentiation of c-Kit+ cells within 1 week maybe due to the urgent needs of hematopoietic regeneration under the myeloablated hosts.
题目: 小鼠造血细胞移植后早期造血重建的动力学变化.
目的: 揭示移植后早期（4 w）供体来源的造血干/祖细胞（hematopoietic stem/progenitor cell, HSPC）以及各类分化成熟血细胞的动态变化特点.
方法: 利用小鼠同种同基因造血干细胞移植模型分别移植供体（B6-Ly5.1）5×106全骨髓单个核细胞（wBMMNC）和富集的3×105 c-Kit+ HSPC到致死剂量照射的同品系受体小鼠（B6-Ly 5.2），然后动态监测移植后早期（4 w内）受体内供体来源细胞的造血重建和谱系分化情况.
结果: wBMMNC移植后1 w（5-7 d）供体来源细胞开始出现增殖，在移植后2-3 w达到增殖高峰；c-Kit+ HSPC移植后第1-2 w供体细胞即出现增殖高峰并一直维持到移植后4 w。 wBMMNC移植后1 w，骨髓中供体来源细胞主要向髓系细胞分化，伴随有少量B细胞生成，而几乎没有T细胞的生成；在移植后2-4 w，供体来源细胞几乎全部分化为髓系细胞。c-Kit+ HSPC移植后1-3 w供体来源细胞几乎全部分化为髓系细胞，移植后4 w时出现B细胞的重建。移植后1-2 w，c-Kit+ 细胞移植组供体来源LKS-和LKS+细胞的绝对数显著高于wBMMNC移植组（P＜0.001）。双光子显微镜观察受体小鼠颅骨发现，c-Kit+ 细胞移植后4-5 d，105及106细胞移植组即可观察到簇状分布的供体来源细胞的增殖.
结论: c-Kit+细胞移植后供体来源HSPC（LKS-和LKS+）重建动力学速率显著快于wBMMNC移植组，c-Kit+细胞移植后1-3 w主要向髓系细胞分化，4 w才开始出现部分淋系分化。c-Kit+细胞移植后1 w之内供体来源HSPC迫于造血压力迅速增殖分化，从而维持机体对于应激造血的迫切需求.