Abstract: Objective To establish an animal model of early primary biliary cirrhosis （PBC） by injection of polyinosinic-polycytidylic acid（Poly I:C）. Methods Thirty female C57BL/6 mice were randomly divided into model and control group. Mice in model group were injected with poly I:C at a dose of 5 mg.kg^-1 while animals in control with equal volume of saline for 24 weeks. The antimitochondrial antibody-M2（AMA-M2）,CD4⁺CD25⁺Foxp³⁺ cells were detected at 8,16 and 24 weeks. Histological changes of liver samples were evaluated with HE, PASM,and masson trichrom staining and CK19 was detected by anti-CD19 antibody staining at each stage. Results The positive rate of AMA-M2 in model group at week 24 was 100%（5/5）,significantly higher than in the control group（0/5）;The percentages of CD4⁺CD25⁺Foxp³⁺ Tregs in the peripheral blood in model group at week 8,16 and 24 were（3.48±0.95）%,（3.30±1.55）% and（2.67±0.97）%,all of which significantly lower than those in the control group at each corresponding time[（7.25±1.63）%,（6.33±1.06）% and（5.58±1.52）%,P<0.05];The expression of CK19 in liver tissues showed no significant difference between the two groups;Liver pathology showed progressively increased infiltration of inflammatory cells around the portal area and bile duct,small bile duct proliferation,bilious fragmental necrosis and bridging fibers in model group. Conclusions The animal model of early PBC is successfully established by injection of Poly I:C and the CD4⁺CD25⁺Foxp3⁺ T cells may play a critical role in the pathogenesis of the entity.

Key words: Primary biliary cirrhosis, Polyinosinic-polycytidylic acid, Mouse, Animal model