中文摘要：

目的探讨异基因骨髓源间充质干细胞（MSC）输注对极重度放射损伤小鼠造血功能重建的影响。方法以C57BL／6（H-2b）雄性小鼠为供体制备MSC单细胞悬液。取雌性BALB／c（H-2d）小鼠120只作为受体，随机分为MSC-A组、MSC-B组、MSC-C组和PBS组（n=30），均接受90Coγ射线致死剂量（8Gy）照射，前3组小鼠于照射后2h分别经尾静脉输注MSC1×10 6、1×10 5、5×10 4／只，PBS组在相同时间点经尾静脉输注等体积（0．4ml）PBS。观察小鼠的生存情况及外周血白细胞（WBC）、血红蛋白（HGB）、血小板（PLT）的变化，进行骨髓单个核细胞、粒-单系祖细胞（CFU-GM）及脾集落形成单位（CFU-S）计数，对Y染色体进行检测，并观察小鼠股骨骨髓的病理学变化。结果各组小鼠经致死剂量照射后，WBC、HGB和PLT均迅速下降，PBS组小鼠于照射后17d内全部死亡。MSCA、MSC-B、MSC-C组小鼠的外周血WBC、HGB、PLT在2周左右开始逐渐恢复，观察至56d，各组小鼠的生存率分别为61．9％、47．6％、38．0％。MSC各治疗组小鼠的生存率、骨髓单个核细胞、CFU-GM、CFUS均明显高于PBS组（P〈0．05），前述各项指标均随MSC输注数量的增加而增加。移植后10d，MSC各治疗组小鼠骨髓中均可检测到Y染色体，但仅在移植后初期短暂植入。MSC输注后42d，MSC各治疗组骨髓增生活跃。结论异基因来源的骨髓源MSC单独输注可促进极重度放射损伤小鼠造血功能重建；随着MSC输注数量的增加，其促造血重建功能增强。

英文摘要：

Objective To explore the effects of allogeneic bone marrow derived mesenchymal stem cells （MSC） infusion on the hematopoiesis reconstitution in mice suffering from severe irradiation injury. Methods MSC mononuclear cell suspension was prepared with male C57BL/6 （H-2b） mice as donors. One hundred and twenty female BALB/c mice （H2d）, as recipients, received lethal dose irradiation of 60Co γ-ray （in a dosage of 115cGy/min for 6. 95 min, a total dose of 8 Gy）, and they were then randomly assigned into 4 groups （30 each） ： MSC-A, MSC-B, MS（; C group （intravenous infusion via caudal vein of MSCs by 1 × 10 6, 1 × 10 5 , 5 × 10 4 cells/ mouse, respectively, 2 hours after irradiation） and PBS group （received isovolumic PBS infusion at the same time point）. The survival rate and the changes in white blood cells （WIK2）, hemoglobin （HGB） and platelets （PLT） were investigated, colony-forming unit of granulocyte-macrophage （CFU-GM） and that of spleen （CFU S） were counted, and Y chromosome was examined, and pathological changes in bone marrow was observed. Results The amounts of peripheral blood WBCs, HGB and PLTs decreased rapidly in mice after being irradiated by lethal dose of 60Co γ-ray. All the mice in PBS group died on day 17 after radiation, and the hemogram of those animals in MSC-A, MSC-B and MSC-C group began gradually to recover around day 14. The survival rates of the 3 groups at day 56 after irradiation were 61.9%, 47. 6% and 38. 0%, respectively. The counts of mononuclear cells, CFU-GM and CFU-S were higher in the 3 treatment groups than in PBS group （P〈0. 05）, and the more MSCs infused, the higher the mononuclear cells, CFU-GM and CFU S counts. Y chromosome was found on day 10 in the marrow of 3 MSC treated groups, however, the implantation only existed briefly in the early period. The bone marrow hyperplasia was observed to be activated on day 42 in the 3 MSC treated groups. Conclusion Allogeneic bone marrow-derived mesenehymal stem eells infusion a