Basic studies on animal model for regenerative medicine using severe immunodeficient mice.

我们最近通过将IL-2Rγγ基因导入NOD-SCID、IL-2R Null&gt；基因，获得了严重免疫缺陷的NOD/SHI-SCID、IL-2R Null&gt；这些小鼠表现出良好的人类细胞发育和分化能力，表明NOG小鼠可以用来产生“人源化小鼠”。在这项研究中，我们调查了NOG小鼠作为再生医学模型的使用。在器官移植中，人的格拉夫卵泡是在将一小片人卵巢移植到肾囊中后发育起来的。将人子宫内膜组织移植到小鼠背部皮下，然后注射人激素，也可以观察到子宫内膜的月经周期。作为胚胎干细胞用于再生医学的模型，我们研究了C57BL/6J来源的胚胎干细胞移植到NOG小鼠不同器官后的体内分化。将ES细胞注入经博莱霉素治疗受损的NOG肺或经四氯化碳治疗受损的NOG肝脏，ES细胞在器官内生长并形成畸胎瘤。然而，ES细胞向肺或肝细胞的分化尚不能得到证实。我们还用SD大鼠建立的胚胎生殖细胞(EG)进行了同样的实验。将大鼠EG细胞注入GFP转基因SD大鼠肺内，经博莱霉素处理后取出肺，皮下移植于NOG小鼠背部。分别于移植后2、4、8周取出移植肺进行组织学检查。结果，植入的肺被部分植入，但EG细胞形成畸胎瘤。这些结果表明，ES细胞必须分化为祖细胞，而不是ES细胞本身，才能用于再生医学。

We recently developed severe immunodeficient NOD/Shi-scid, IL-2Rγ KO (NOG) mice by introducing IL-2Rγ^<null> gene into NOD-scid mice. These mice show excellent development and differentiation of human cells, indicating the usefulness of NOG mice to generate "humanized mice". In this study, we investigated the use of NOG mice as models for regenerative medicine. For organ transplantation, human Graff follicles were developed when a small piece of human ovary was transplanted into a renal capsule. The menstrual cycle in the endometrium was also observed when human endometrial tissue was subcutaneously transplanted in the back of the mice followed by injection of human hormones. As a model for regenerative medicine using embryonic stem (ES) cells, we investigated in vivo differentiation of C57BL/6J-derived ES cells after their transplantation in various organs of NOG mice. When ES cells were injected into NOG lungs impaired by treatment with bleomycin or NOG livers impaired by treatment with carbon tetrachloride, ES cells grew and formed teratomas in the organs. However, differentiation of ES cells into lung or liver cells could not be confirmed. We also performed the same experiment using embryonic germ (EG) cells established from SD rats. After rat EG cells were injected into the lung of GFP transgenic SD rats impaired by treatment with bleomycin, the lung was removed and subcutaneously transplanted into the back of NOG mice. At 2, 4 and 8 weeks after transplantation, the implanted lungs were removed and examined histologically. As a result, the implanted lungs were partially engrafted, but the EG cells formed tereratomas. These results suggest that ES cells must be differentiated into progenitor cells but not ES cells by themselves for use in regenerative medicine.