The role of CXCR3 knockout in alleviating the primary biliary cirrhosis in mice / 中华风湿病学杂志

ABSTRACT

Objective To generate an autoimmune cholangitis animal model and investigate whether CXCR3 and its ligand were involved in the pathogenesis of primary biliary cirrhosis (PBC). Methods Female C57BL/6 wild-type (WT) mice and CXCR3 knockout (CXCR3-/-) mice were injected with 5 mg/kg of poly I:C intra-peritoneally twice a week for 24 consecutive weeks. Liver specimens were collected to evaluate the degree of cell infiltration. AMA was assayed by ELISA. Differences in pathology were compared between CXCR3-/- mice and wild-type. Student's test was used to assess the differences. Results Anti-mitochon-drial antibody (AMA) and alkaline phosphatase (ALP) level were elevated significantly in the sera of all poly Ⅰ:C injected mice compared with control mice. AMA titers in serum were increased in the poly I:C injected WT mice compared with that of the control mice at week 8, 16, and 24 respectively (0.70±0.41 vs 0.17±0.04,0.48±0.35 vs 0.19±0.07, 0.69±0.44 w 0.20±0.06, P＜0.01). There was no significant difference between AMA titers in the serum of WT PBC mice and CXCR3-/- PBC mice (0.70±0.41 vs 0.56±0.25, 0.48±0.35 vs 0.46±0.35, 0.69±0.44 vs 0.85±0.34). Serum alkaline phosphatase (ALP) levels were raised among the poly I:Cinjected WT mice compared with WT controls (115±33) vs (65±7) U/ml; (119±32) vs (70±9) U/ml; (133±52) vs (77±10) U/ml. The serum ALP levels in CXCR3-/- PBC mice were (106±29), (112±29)and (122±60) U/ml at week 8, 16 and 24 respectively. There was no significant difference in ALP level between WT and CXCR3-/- mice PBC model. Considerable numbers of infiltrating cells were detected at the portal areas 8weeks after poly I:C injection, which progressed up to 24 weeks. At week 24, the interlobular bile ducts were lost and bile-plug were evident. Compared to WT mice model, this results revealed that CXCR3-/- mice, had fewer foci of inflammation and significant reduction in total inflammatory cells in their livers than those of the WT mice at 8, 16 and 24 weeks after injection of poly I:C. At week 24, there were no cholestasis orgranulomas in CXCR3-/- mice of PBC models. Compared to the control model, CXCL10 serum level was increased in PBC model. With the disease progression, CXCL10 serum level was elevated gradually. In comparison with wild mice, CXCR3-/- mice model had a higher serum level of CXCL10. At week 24, there was significant difference of CXCL10 serum level between wild-type mice and CXCR3-/- mice model. Conclusion In conclusion, these findings indicate that, CXCR3-/- mice might have a delayed onset and ultimately could not recruit sufficient effector cells to the liver for inflammation development.