Preparation For The Human-Mouse Liver Chimerica By Human Stem Cells

Part One: The establishment of human-mouse chimerica using human cord blood stem cell.Objectives: to establish a human-mouse chimerica by in vitro transplantation of human cord blood stem cells. Methods: Human cord blood stem cells were injected twice into the bodies of nude mice via tail veins. The hepatic tissues were collected at day 7, 14 and 21 fallowing the injection of Human cord blood stem cells, the alpha-fetoprotein(AFP) was tested by immunohistochemmistry to investigate the chimerical growth of human liver cells in the mice. The mice then were infected by hepatitis B virus(HBV) and the serum AFP and albumin(ALB) were quantitatively tested in the comparison with normal nude mice. Results: the AFP was continuously expressed in the liver cytoplasm of mice at the 7th, 14th and 21st days fallowing the human cord blood stem cells injection. There were dense HBsAg positive cells observed in mice liver Infected with HBV by immunohistochemistry which were significant different from those in the control (P<0.05). Conclusions: human cord blood stem cells transplanted into the mouse liver could survive therein and differentiate into human hepatic cells, thus forming the chimerica, which were able to be infected by HBV.Part Two: The establishment of human-mouse chimerica using human myeloid stem cell.Objectives: to establish a human-mouse chimerica by in vitro transplantation of human myeloid stem cells. Methods: Human myeloid stem cells in the amount of 1×10~9 per mouse were directly injected into the fetus hepatic tissues of mice by surgery. The human serum AFP and ALB in the transplanted mice were tested immunohistochemistrically at 2nd, 4th, 6th and 12th months after birth to investigate the chimerical growth of human liver cells in the mice. In addition, the mice were also infected by hepatitis C virus(HCV). Results: The human serum AFP content in transplanted mice at ages of 2, 4, 6 and 12 months were significantly higher than that of normal mice. The immunohistochemistrically positive hepatic cells of human AFP and ALB were observed at age of 2nd and 12th months. The mice infected by HCV showed a positive rate of 66.67%. Conclusions: Human myeloid stem cells could be chimerised into mouse liver and differentiate into human hepatic cells which are able to survive more than 12 months and to be infected by HCV.