OBJECTIVETo establish a rat model for hepatic oval cell proliferation and to observe the relationship between 2-acetaminofluorene (AAF) dosage and oval cell proliferation in the rat liver.

METHODSMale Wistar rats weighing 150 g received daily oral gavage of AAF for 4 days before operation and up to 7 days after operation. Two-thirds hepatectomy was performed on the 5th day and the gavage was not performed on the day of operation. AFF was given with the dosage of 2.5 mg/kg, 5 mg/kg, 10 mg/kg, 15 mg/kg, and 20 mg/kg body weight. Animals in control group were given saline. Three rats from each group were killed every 2~3 days after hepatectomy and liver slices were fixed and processed for routine histology and immunohistochemistry.

RESULTSHepatic oval cells were not observed in the liver of controls and only a few were detected in the liver of 2.5 mg/kg and 5 mg/kg groups. However, obvious oval cell proliferation was seen in the liver of 10 mg/kg, 15 mg/kg, and 20 mg/kg groups. Hepatic oval cells were stained positive for cytokeratin 19, OV6, vimentin and proliferating cell nuclear antigen (PCNA).

CONCLUSIONSSatisfactory rat models for hepatic oval cell proliferation can be obtained using our scheme when AAF is dosed at 10~20 mg/kg body weight.