title: Generation of human/rat xenograft animal model for the study of human donor stem cell behaviors in vivo.
abstract: OBJECTIVE
  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 beta2-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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Center of Experimental Animals, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Sun
authors.forename: Dong
authors.initials: D
authors.lastname: Xiao
authors.forename: Xing-Hua
authors.initials: XH
authors.lastname: Pan
authors.forename: Ruo-Shuang
authors.initials: RS
authors.lastname: Zhang
authors.forename: Guang-Hui
authors.initials: GH
authors.lastname: Cui
authors.forename: Xi-Gu
authors.initials: XG
authors.lastname: Chen
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D049109:Cell Proliferation; D002678:Chimera / Q000502:physiology; D036101:Cord Blood Stem Cell Transplantation; D005260:Female; D005333:Fetus / Q000473:pathology; D006412:Hematopoietic Stem Cells / Q000473:pathology* / Q000502:physiology*; D006801:Humans; D007150:Immunohistochemistry; D023421:Models, Animal; D036102:Peripheral Blood Stem Cell Transplantation; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D051381:Rats; D014183:Transplantation, Heterologous / Q000473:pathology* / Q000502:physiology*