Abstract: To establish a rat model for hepatic oval cells proliferation and to analyze the characterization of oval cell,SD rats （about 150 g） were given 2-acetylaminofluorene （2-AAF）6 days before partial hepatectomy and 7 days after it. Liver tissue specimens were obtained every 2?3 days after partial hepatectomy and were investigated by HE staining and immunohistochemical staining for Brdu，OV6，cytokeratin-19，albumin，AFP, connexin-43 and C-kit. Oval cells were enriched by magnetic activated cell sorting （MACS） using C-kit antibody.RT-PCR was per-formed on sorted cells for the albumin，AFP and CK19 messenger RNA expression. Results：Ob-vious oval cell proliferation was seen in the liver in 10 mg/kg，15 mg/kg,20 mg/kg groups and o-val cell Brdu incorporation test is positive. Oval cells expressed the specific marker OV6，hepatic cell marker albumin, biliary cell marker CK19，fetal liver cell marker AFP and connexin-43 as well as hematopoietic stem cell receptor C-kit. More than 90% sorted oval cells were OV6 positive and all expressed the albumin,AFP and CK19 gene. Conclusions：Rat model for hepatic oval cell proliferation can be established with 2-AAF/partial hepatectomy at dosage of 10?20 mg/kg body weight. And such oval cells were hepatic stem/progenitor cells which expressed OV6/ CKl9/albumin/AFP/connexin43/C-kit. Oval cell population can be highly enriched with MACS using C-kit.

Key words: Oval cell, Hepatice progenitor cell, Stem cell, Immunohistochemistry