Basic Research
Copyright ©2007 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. May 21, 2007; 13(19): 2707-2716
Published online May 21, 2007. doi: 10.3748/wjg.v13.i19.2707
Generation of human/rat xenograft animal model for the study of human donor stem cell behaviors in vivo
Yan Sun, Dong Xiao, Xing-Hua Pan, Ruo-Shuang Zhang, Guang-Hui Cui, Xi-Gu Chen
Yan Sun, Ruo-Shuang Zhang, Guang-Hui Cui, Xi-Gu Chen, Center of Experimental Animals, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China
Dong Xiao, Institute of Comparative Medicine and Center of Experimental Animals, Southern Medical University, Guangzhou 510515, Guangdong Province, China
Xing-Hua Pan, Clinic Experimental Department, Kunming General Hospital, Chengdu Military District of PLA, Kunming 650032, Yunnan Province, China
Author contributions: All authors contributed equally to the work.
Supported by The National Natural Science Foundation of China, No. 30271177 and No. 39870676; the National 9th Five-year Program, No. 101033; The Major Science and Technology Projects of Guangdong Province, No. B602; Natural Science Foundation of Guangdong Province, No. 021903; The Postdoctoral Fellowship Foundation of China (Series 29); The Special Fund of Scientific Instrument Collaborative Share-net in Guangzhou, No. 2006176
Correspondence to: Xi-Gu Chen, Professor, Center of Experimental Animals, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China. xiguchen1516@yahoo.com.cn
Telephone: +86-20-33151566 Fax: +86-20-87331230
Received: March 7, 2007
Revised: March 14, 2007
Accepted: April 11, 2007
Published online: May 21, 2007
Abstract

AIM: To accurately and realistically elucidate human stem cell behaviors in vivo and the fundamental mechanisms controlling human stem cell fates in vivo, which is urgently required in regenerative medicine and treatments for some human diseases, a surrogate human-rat chimera model was developed.

METHODS: Human-rat chimeras were achieved by in utero transplanting low-density mononuclear cells from human umbilical cord blood into the fetal rats at 9-11 d of gestation, and subsequently, a variety of methods, including flow cytometry, PCR as well as immunohistochemical assay, were used to test the human donor contribution in the recipients.

RESULTS: Of 29 live-born recipients, 19 had the presence of human CD45+ cells in peripheral blood (PB) detected by flow cytometry, while PCR analysis on genomic DNA from 11 different adult tissues showed that 14 selected from flow cytometry-positive 19 animals possessed of donor-derived human cell engraftment in multiple tissues (i.e. liver, spleen, thymus, heart, kidney, blood, lung, muscle, gut and skin) examined at the time of tissue collection, as confirmed by detecting human β2-microglobulin expression using immunohistochemistry. In this xenogeneic system, the engrafted donor-derived human cells persisted in multiple tissues for at least 6 mo after birth. Moreover, transplanted human donor cells underwent site-specific differentiation into CK18-positive human cells in chimeric liver and CD45-positive human cells in chimeric spleen and thymus of recipients.

CONCLUSION: Taken together, these findings suggest that we successfully developed human-rat chimeras, in which xenogeneic human cells exist up to 6 mo later. This humanized small animal model, which offers an in vivo environment more closely resembling to the situations in human, provides an invaluable and effective approach for in vivo investigating human stem cell behaviors, and further in vivo examining fundamental mechanisms controlling human stem cell fates in the future. The potential for new advances in our better understanding the living biological systems in human provided by investigators in humanized animals will remain promising.

Keywords: Human umbilical cord blood-derived cells; In utero xenogeneic transplantation; Human-rat chimeras; Embryonic microenvironment; In vivo model