Expression and clinical significance of bile salt export pump in rat liver with bile duct obstruction and bile reflow

Objective To explore the role of bile salt export pump (BSEP) in rat liver with bile duct obstruction and bile reflow. Methods Fifty-four male Wistar rats were randomizedly divided into three groups, sham group, common bile duct ligation (CBDL) group and bile reflow (BR) group to detect level of serum ALT, total bile acids (TBA) and tumor necrosis factor-α (TNF-α) at every time point. Expression of BSEP at level of gene transcription, protein expression and hepatic cell membrane localization was measured by using RT-PCR and immunohistochemistry method. Mean BSEP-IOD was detected semi-quantitatively by using Mias99 pathological image analysis system. Meanwhile, correlation of BSEP-IOD with serum TBA and TNF-α was performed. Results After CBDL, levels of serum ALT, TBA and TNF-α were ascended significantly (P0.05), which got a gradually favourable turn but was still higher than that in sham group seven days after bile reflow (P0.05). The expression of BSEP mRNA decreased as bile duct obstruction elongated (P0.05), increased slowly 14 days after CBDL and posterior to obstruction relief but did not reach level of sham group seven days after BR. Immunohistochemistry results showed a similar tendency to above-mentioned change, ie, expression of BSEP was restrictively located on the hepatocyte membrane, which was negatively correlated with TBA and TNF-α (r_1=-0.9257,r_2=-0.8536,P0.05). Conclusion BSEP may be responsible for bile salt metabolism in rat model of bile duct obstruction and bile reflow, and TNF-α plays an important role in regulating BSEP expression.