To study the mechanism and action of Cinnamomi Ramulus in ameliorating intrahepatic cholestasis induced by α-isothiocyanate( ANIT) in rats by regulating FXR pathway. Forty SD rats were randomly divided into normal group,model group,positive control( ursodeoxycholic acid) group( 60 mg·kg~(-1)),Cinnamomi Ramulus treatment( 60 mg·kg~(-1)·d~(-1)) group,and Cinnamomi Ramulus treatment( 20 mg·kg~(-1)·d~(-1)) group,with 8 rats in each group. Except for the normal control group,the other groups were intragastrically administered with the corresponding concentrations of continuous aqueous solution( 0. 005 m L·g~(-1)),once a day,for 7 days.Except for the normal group,the other groups were treated with ANIT( 100 mg·kg~(-1)),once a day,for 3 days. Blood was taken from the abdominal aorta 24 hours after the last administration,and serum alanine aminotransferase( ALT),aspartate aminotransferase( AST),total bilirubin( TBi L),and total bile acid( TBA) were measured. 1. 5-2 cm of rat liver tissue was taken. After fixation with10% formaldehyde,paraffin-embedded sections were taken,HE staining was performed,and immunohistochemistry( IHC) was used to analyze the expression of FXR. RNA and protein were extracted from rat liver tissue to detect FXR mRNA expression,as well as bile acid synthesis and detoxification,transport related SHP,UGT2 B4,BSEP protein expressions at downstream of FXR. Compared with the normal group,serum ALT,AST,TBi L,and TBA levels were elevated in the model group( P<0. 01),liver damage was severe,FXR protein's optical density decreased,FXR mRNA expression decreased,and SHP,UGT2 B4,BSEP protein expressions were decreased( P<0. 05,P<0. 01). Compared with the model group,the drug group could reduce serum ALT,AST,TB,TBA levels to different degrees( P<0. 05,P<0. 01),alleviate liver tissue damage,increase the optical density of FXR protein,and promote the expressions of FXR mRNA and FXR,SHP,BSEP and UGT2 B4 proteins( P<0. 05,P<0. 01). Cinnamomi Ramulus can alleviate ANIT-induced intrahepatic cholestasis,and reduce hepatocyte injury and serum ALT,AST,TBi L and TBA levels. The mechanism may be through FXR-SHP,FXR-UGT2 B4,FXR-BSEP signaling pathways. Therefore,in the pathogenesis of intrahepatic cholestasis,we can try to further explore in alleviating intrahepatic cholestasis with Cinnamomi Ramulus,so as to provide effective drugs for clinical treatment of intrahepatic cholestasis.
Keywords: Cinnamomi Ramulus; FXR; cholestasis; collaterals; α-isothiocyanate(ANIT).