Expression of intrahepatic chemokine CXCL13 in a mouse model of primary biliary cholangitis / 医学研究生学报

ABSTRACT

Objective The expression of chemokine C-X-C motif ligand 13 (CXCL13) within liver in primary biliary cholangitis (PBC) patients is significantly increased, but its origin and mechanism is not clear yet.The study aimed to investigate the expression of CXCL13 in the liver of mice through establishing a mouse model of PBC.Methods C57BL/6 mice were randomly divided into experiment group (n=20) control group(n=10).The mice in the experimental group were intraperitoneally injected with polyriboinosinic polyribocytidylic acid (Poly I:C) while the mice in control group were injected with PBS of the same volume.The level of serum AMA was quantified by ELISA and intrahepatic inflammatory cells were assessed by HE staining.Kupffer cells, liver sinusoidal endothelial cells, and infiltrating lymphocytes in the liver of mice were collected by in situ perfusion enzyme digestion and magnetic bead separation methods.The transcriptional level of intrahepatic CXCL13 in liver tissues and cell subpopulations were detected by qPCR.Results The serum AMA titers of the mice in experiment group increased gradually with the prolonging of modeling time and the positive rates at the 4th, 8th, and 12th week after the first injection of Poly I:C were 5.9%, 52.9% and 76.5% respectively.While the serum AMA titers of the mice in control group were at a lower level through the modeling process, with only 2 mice presenting a little higher level above positive cutoff value at the 12th week.The results of HE staining in liver tissues of both groups showed that there were a great amount of intensely infiltrating inflammatory cells in the mice of experimental group while no inflammatory cell infiltration were found in the mice of control group.The separation purity of Kupffer cells and liver sinusoidal endothelial cells in the mice of experiment group tested by flow cytometry were 76%-80%, 68%-72% respectively.Compared with the CXCL13 mRNA level in Kupffer cells [2.34(0.22-8.64)], the expression levels in liver sinusoidal endothelial cells and infiltrating lymphocytes declined[0.27(0.03-1.64), 0.05(0-0.22), P<0.05].Conclusion The chemokine CXCL13 is predominantly produced by Kupffer cells in the liver of PBC mice established by Poly I:C injection.