Yoshizato Project, Cooperative Link of Unique Science and Technology for Economy Revitalization (CLUSTER), Hiroshima Prefectural Institute of Industrial Science and Technology, Higashihiroshima, Hiroshima, Japan.
Xenotransplantation. 2013 Jul-Aug;20(4):227-38. doi: 10.1111/xen.12037. Epub 2013 May 20.
We previously generated humanized chimeric mice by transplanting h-hepatocytes into the livers of the diseased-liver transgenic mouse model with immunodeficient background. These mice with livers mostly replaced by human (h) hepatocytes have been proved to be useful for research on drug metabolism and toxicity and on intrahepatic pathogens such as hepatitis. However, their small body size prohibited collecting sufficient biological samples and made surgical manipulation difficult, which motivated us to produce humanized larger animal(s) bearing h-hepatocytes.
Fischer 344 (F344) rats at 2 weeks of age were administrated with hepatotoxin retrorsine (RS) and then transplanted with syngeneic F344 rat (r)- or h-hepatocytes via the portal vein. The hosts were injected daily with FK506 immunosuppressant. The livers were harvested periodically for determining donor-cell replacement ratios and compared with those of the humanized chimeric mice, and liver-specific mRNA and protein expressions by immunohistochemistry and reverse-transcription PCR.
RS treatment of infant rats inhibited hepatocyte proliferation, resulting in decreased liver weight and megalocytic changes in hepatocytes. R-hepatocytes transplanted into RS-treated rats engrafted into and repopulated the liver at ratios of 16.4 ± 6.7% and 48.3 ± 29.3% at 3 and 6 weeks after transplantation, respectively. H-hepatocytes also engrafted into the rat liver and showed a repopulation ratio of 2.5 ± 1.5% at 3 weeks post-transplantation, which was comparable to the ratio in the humanized chimeric mouse model at least until 3 weeks. Propagated h-hepatocytes in the rat liver expressed hepatocyte-specific mRNA and proteins at least 3 weeks after transplantation.
Xenogeneic hepatocytes were able to engraft rat liver and grow well therein for at least 3 weeks post-transplantation in rats when immunosuppression was combined appropriately with liver injury at comparable levels to the well-characterized humanized chimeric mouse model.
我们之前通过将 h 肝细胞移植到免疫缺陷背景的肝病转基因小鼠模型的肝脏中来产生人源化嵌合小鼠。这些肝脏大部分被（h）肝细胞取代的小鼠已被证明可用于药物代谢和毒性以及肝内病原体（如肝炎）的研究。然而，它们的体型较小，限制了足够生物样本的收集，并且使手术操作变得困难，这促使我们产生具有 h 肝细胞的人源化较大动物。
2 周龄的 Fischer 344（F344）大鼠给予肝毒素 retrorsine（RS），然后通过门静脉移植同基因 F344 大鼠（r）或 h 肝细胞。宿主每天接受 FK506 免疫抑制剂注射。定期收获肝脏以确定供体细胞替代率，并与嵌合小鼠模型进行比较，通过免疫组织化学和逆转录 PCR 检测肝特异性 mRNA 和蛋白表达。
RS 处理婴儿大鼠抑制肝细胞增殖，导致肝重降低和肝细胞巨细胞变化。移植到 RS 处理大鼠肝脏中的 r 肝细胞在移植后 3 和 6 周时分别以 16.4±6.7%和 48.3±29.3%的比例植入并重新定植肝脏。h 肝细胞也植入大鼠肝脏，并在移植后 3 周时表现出 2.5±1.5%的再定植比例，至少在 3 周内与嵌合小鼠模型的比例相当。在移植后至少 3 周，在大鼠肝脏中增殖的 h 肝细胞表达肝细胞特异性 mRNA 和蛋白。
在适当的免疫抑制与肝损伤相结合的情况下，异种肝细胞能够植入大鼠肝脏并在其中良好生长，至少在 3 周内与经过充分表征的人源化嵌合小鼠模型相当。
