Abstract: Abstract:Objective To observe the changes of transport protein Farnesoid X receptor (FXR) and bile salt export pump (BSEP) in liver cells of obstructive jaundice rats,and to discuss the influence of FXR activation and endotoxin (ET) on the expression of BSEP.Methods  Thirty-six healthy SD rats were randomly divided into sham operation group (Sham group),common bile duct ligation (CBDL) group and bile reflow (BR) group.The FXR and BSEP transcription and protein levels of hepatocytes were measured with average optical density (AOD) and immunohistochemistry microscope in liver tissues from the three groups at each time point.Meanwhile,the levels of serum total bilirubin(TBIL),total bile acid (TBA) and ET were examined with conventional methods.The relationships between FXR,TBA,ET and BSEP were analyzed by linear correlation analysis.Results The serum levels of TBIL,TBA and ET of rats in sham group at each time point after operation had no change(P>0.05);the serum levels of TBIL,TBA and ET of rats in CBDL group after CBDL were significantly increased(P<0.01);the serum levels of TBIL,TBA and ET of rats in BR group after BR were gradually decreased,the levels of TBIL and TBA 7 d after BR had no difference compared with sham group(P>0.05),but the ET level was also higher than that in sham group(P<0.05).The expression levels of FXR in  sham,CBDL and BR groups were increased gradually and slowly,but no significant differences were found among three groups (P> 0.05).The expression levels of BSEP in  sham and BR groups tended to decrease with time;the expression level of BSEP in  CBDL group was decreased firstly and then was increased,there was  no significant differences compared with  sham group (P> 0.05).Positive correlation was found between the genetic expression levels of FXR and TBA (r=0.303,P< 0.05),while negative correlation was found between the expressions of FXR and BSEP (r=－0.359,P< 0.05).The  expression levels of BSEP and ET were also negatively correlated (r=－0.412,P< 0.01).Conclusion The FXR level doesn’[KG-*3]t  play a leading role in the  expression of BSEP in the obstructive jaundice rats.The down-regulation of BSEP expression is mainly due to the expression level of ET.

Key words: obstructive jaundice, bile acid, f
arnesoid X receptor, bile salt export pump, endotoxin