辐照小鼠骨髓移植后造血和免疫系统重建的动态过程

Dynamic processes of hematopoietic and immune reconstitution after irradiated mice receiving bone marrow transplantation

目的研究小鼠骨髓移植后造血和免疫系统重建的动态过程,为优化造血干细胞移植治疗方案和药物研究提供支持。方法60只CD45.2^(+)雄性C57BL/6小鼠作为受体鼠,随机均分为正常对照组和移植组,移植组经致死剂量钴60射线全身照射后,经尾静脉输注移植CD45.1^(+)雄性C57BL/6小鼠骨髓细胞,正常对照组尾静脉注射等体积PBS。移植后1,2,4,8和16周取2组受体鼠外周血、脾、淋巴结、胸腺和骨髓,外周血进行血常规检测,其他样本制备细胞悬液后利用自动细胞计数仪测定细胞总数,用荧光抗体染色,用流式细胞术分析髓系白细胞和红细胞祖细胞比例、巨核细胞及其祖细胞比例及造血干细胞比例。结果骨髓移植后4周,移植组小鼠外周血白细胞和红细胞数量恢复至正常对照组同等或更高水平(P<0.05);血小板数量虽有明显恢复,但直至16周仍低于正常对照组(P<0.05)。骨髓移植后4周,移植组小鼠外周血、脾、淋巴结和骨髓中髓系白细胞和B细胞及骨髓中巨核细胞和红细胞祖细胞的比例恢复至正常对照组同等水平,且髓系白细胞和B细胞均由自供体的CD45.1^(+)细胞占据主导地位。骨髓移植后8周,移植组受体小鼠外周血、脾、淋巴结、胸腺和骨髓中T细胞的比例恢复至正常对照组相同水平,并以CD45.1^(+)T细胞占据主导地位。结论骨髓移植后8周,受体小鼠的造血和免疫系统重建基本完成,但不同细胞的重建速度及同种细胞在不同部位的重建动态过程具有较大差异。

OBJECTIVE To optimize hematopoietic stem cell transplantation therapy and provide support for drug research by investigating the dynamic process of hematopoietic and immune system reconstitution after bone marrow transplantation(BMT)in mice.METHODS CD45.2^(+)C57BL/6 mice were used as recipient mice and randomly divided into the normal control group and transplantation group,with 30 mice in each.The transplantation group was irradiated by a lethal dose of cobalt-60 rays.Bone marrow cells were prepared from CD45.1^(+)C57BL/6 mice and transfused into recipient mice through the tail vein.Peripheral blood,spleens,lymph nodes,thymuses and bone marrow were collected at 1,2,4,8 and 16 weeks after transplantation.Blood routine examination was performed with peripheral blood and total cell numbers in suspensions of other organs were counted by an automated cell counter.Cell classification analysis of white blood cells in peripheral blood,cell suspensions of other organs was performed by flow cytometry.RESULTS Four weeks after BMT,the numbers of white blood cells and red blood cells in peripheral blood of recipient mice returned to the same level of or higher level than normal control(P<0.05).Although the number of platelets recovered significantly,it was still mark⁃edly lower than that of normal control until 16 weeks post BMT(P<0.05).In addition,the percentages of myeloid leukocytes and B cells in peripheral blood,spleens,lymph nodes,and bone marrow,as well as megakaryocytes and erythrocyte progenitor cells in bone marrow also returned to normal,and the majority of myeloid leukocytes and B cells were CD45.1^(+)cells from the donors.Eight weeks after BMT,T cells in peripheral blood,spleens,lymph nodes,thymuses,and bone marrow of recipient mice returned to normal,and CD45.1^(+)T cells were dominating.CONCLUSION The hematopoietic and immune reconstitution of recipient mice is nearly completed eight weeks after BMT.However,the reconstruction speed of different kinds of cells and the reconstruction status of same kind of cell in different organs vary widely.