小鼠H-2半相合非清髓同种异基因造血干细胞移植模型的建立及其相关研究

为了探讨小鼠主要组织相容性抗原 (H 2 )半相合非清髓移植中预处理方案的可行性、移植后的造血重建、嵌合体水平及GVHD的发生情况 ,以CB6F1小鼠为受鼠 ,分为 3组 ,移植前 5天开始给予预处理 ,A组给予清髓(10 .5Gy)预处理方案 ,B组给予全身照射 (2Gy) Ara C Cy ,C组为全身照射 (2Gy) Ara C Cy Flu ,对所有受鼠均未进行GVHD防治。所有受鼠在第 0天经尾静脉注射C5 7BL 6小鼠混合细胞悬液 (2× 10 7骨髓细胞 1×10 7脾细胞 ) ,然后观察其造血恢复、植入及移植物抗宿主病 (GVHD)的情况。结果表明 :A组植入结果始终为完全供者型嵌合体 ,B和C组则为混合型或完全供者型嵌合体 ,其中B组混合嵌合体保持在 80 %以下 ,且在移植 5 0天以后有下降趋势 ,而C组嵌合体水平保持在 80 %以上 ,其嵌合接近或为完全供者型 ,移植 5 0天以后仍保持稳定。由于没有给予GVHD防治措施 ,各组均发生不同程度的GVHD ,其中A组受鼠GVHD的发生率和死亡率明显高于B和C两组 (P≤ 0 .0 1) ,但B和C两组之间无显著差异。结论 :以氟达拉宾为主的非清髓预处理方案 ,能够在受者体内形成稳定且持久的植入 ,并通过在受者体内形成混合性嵌合体 ,诱导供体对受体的特异免疫耐受 ,减少或避免GVHD的发生。

Establishment of Nonmyeloablative Allogeneic Stem Cell Transplantation model in H-2 Haploidentical mice and Its related Study

To explore the feasibility of nonmyeloablative conditioning regimens, hematopoietic reconstitution, chimera level and the occurrence of GVHD after nonmyeloablative allogeneic stem cell transplantation in H-2 haploidentical mice, CB6F1 mice were used as the recipient and were divided into 3 groups, mice were pretreated five days before transplantation. Group A was pretreated with myeloablative conditioning regimens (TBI with 10.5 Gy), group B was pretreated by TBI (2 Gy) + Ara-C + Cy and group C-TBI (2 Gy) + Ara-C + CY + Flu, respectively. For all recipient mice, the prevention of GVHD was not given, and 2 x 10(7) bone marrow cells mixed 1 x 10(7) spleen cells from C57BL/6 mice were injected through tail vein on day 0, and then hematopoietic recovery, engraftment and GVHD of recipients were observed. The results of chimera detection after transplantation showed that the engraftment of group A remained full donor chimerism, and engraftments of group B and group C were associated with mixed chimerism or full donor chimerism, but the chimerism of group B remained below 80% and tended to decrease after 50 days whereas chimerism of group C was above 80% (chimerism close to or being full donor type) and preserved even after 50 days. GVHD occurred in all the recipient mice due to that prevention was not given, wherein the occurrence and death rate of GVHD in group A was obviously higher than that of group B and group C (P <0.01), but there was no statistical difference between group B and group C. In conclusion, the nonmyeloablative conditioning regimens mainly based on fludarabine can form stable and lasting engraftment in the body of recipients. The mixed chimerism established in recipients induce tolerance of transplantation and decrease or avoid the occurrence of GVHD.