在人-小鼠异种移植模型中提高人红细胞产生效率条件的优化

本研究旨在探讨在建立人-小鼠异种移植模型中提高人红细胞产生效率的条件。本研究从三个方面分别进行条件优化：①受体免疫缺陷小鼠品系选择，分别对NOD／SCID和NOD／SCID／IL2rγnull两种小鼠品系进行移植，考察移植后不同品系小鼠嵌合率和人红细胞发育情况；②考察照射剂量和照射方法对小鼠生存率的影响；③优化人造血干细胞培养条件及感染方法，检测重建率及红细胞产生率。结果表明，移植后4周检测小鼠骨髓细胞显示，NOD／SCID／IL2rγnull小鼠人CD45比例可达（51．4±13．9）％，并能检测到人红细胞（5．98±3．46）％；利用x射线分2次对小鼠进行总剂量2．5Gy的照射，照射后小鼠生存率可以达到100％；利用新鲜脐带血分离的CD34＋细胞，不经过冻融和分选过程，在分离后72h内完成转染和移植过程，移植后嵌合率可达（51．4±13．9）％，并且人红细胞产生的效率为（5．98±3．46）％。结论：利用x射线分两次照射NOD／SCID／IL2rγnull小鼠后通过尾静脉注射2×10^5个细胞，新鲜分离的人脐带血CD34＋细胞在移植前缩短体外培养时间（≤72h），有利于提高免疫缺陷小鼠体内人红细胞产生效率。

Optimization of Conditions for Human Erythropoiesis in Human- mouse Xenotransplant Model

This study was purposed to investigate the conditions for improving human-mouse xenoengraftment and the erythroid differentiation of human hematopoietic stem cells （HSC） in the xenotranplant model. The engraftments of different mouse strains（ NOD/SCID or NOD/SCID/IL2rγnull）, schemes of irradiation（ single-time or 2-times radiation; Co60γ-ray or X-ray） and strategies of CB CD34＋ cells ex vivo culture time and lentivirus infection were compared. The results showed that at 4 weeks after transplantation, the ratio of hCD45 positive cells in bone marrow of NOD/SC1D/ IL2rγnull mice increased to （51.4 ±13.9） %, and erythroid precursor could be detected. All of the mice receiving X-ray irradiation for 2 times （ a dose of 1 Gy, then the second of 1.5 Gy, with an interval of 15 min） survived. Fresh isolated CB CD34＋ cells were cultured and infected with lentivirus for 72 h and then transplanted into receptor mouse. After 4 weeks, higher engraftmenthCD45 （ 51.4± 13.9 ） % ] and better erythroid development hCD71＋ GPA＋ （ 5.98 ± 3.46） % ] were observed. It is concluded that NOD/SCID/IL2rγnull mice receiving X-ray irradiation for 2 times and were injected with fresh isolated CB CD34＋cells cultured and infected with lentivirus ex vivo within 72 h show a better xenoengraftment and erythroid development.