Physiol. Res. 54: 419-428, 2005

Expression of MRP2 and MDR1 Transporters and Other Hepatic Markers in Rat and Human Liver and in WRL 68 Cell Line


1Department of Histology and Embryology, 2Department of Pharmacology, Faculty of Medicine in Hradec Králové, Charles University, and 3Department of Radiobiology, Purkyně Military Medical Academy, Hradec Králové, Czech Republic

Received July 28, 2004
Accepted October 11, 2004
On-line available December 9, 2004

Here we describe a comparative study of phenotypic properties of hepatic cells in situ and in vitro. We analyzed the expression levels and distribution patterns of ABC transporters MRP2 and MDR1, pan-cytokeratin, cytokeratin 18, albumin, alpha-fetoprotein and the specific hepatocyte marker OCH1E5 in the fetal and adult rat as well as human liver tissue and in human fetal hepatocytes of WRL 68 cell line using peroxidase immunohistochemistry or immunofluorescence. Transporters MRP2 and MDR1 were expressed in all examined liver tissues, except rat ED13 embryo. The immunopositivity of these proteins was localized to the canalicular membrane of differentiating and mature hepatocytes but in the later developmental stages and in the adult liver tissues it was also found in the apical membrane of cholangiocytes. In WRL 68 cells, MRP2 and MDR1 immunoreactivity appeared after 5-6 days of cultivation and both transporters were fully expressed in the plasmalemma and in the cytoplasm 9 days after the passage. In conclusion, we observed only moderate variances reflecting diverse ontogenetic phases between the fetal and adult liver tissue. To study functions of hepatocytes in vitro, WRL 68 cells have to differentiate prior to the examination. Our findings indicate that WRL 68 cells can undergo differentiation in vitro and their antigenic profile closely resembles hepatocytes in the human liver.

Key words
MRP2 protein • MDR1 protein • WRL 68 cell line • Liver • Immunohistochemistry

© 2005 by the Institute of Physiology, Czech Academy of Sciences