Effect Of Emodin On Expression Of Transporter Genes Related To Intrahepatic Cholestasis Of Rats

Background: Cholestasis, an impairment or cessation in the flow of bile, causes hepatocoxicity due to the buildup of bile acids and other toxins in the liver. Cholestasis is a component of many liver diseases, including cholelithiasis, cholestasis of pregnancy, primary biliary cirrhosis (PBC), and primary sclerosing cholangitis. The normal bile flow is fulfilled by the activity of a large panel of transporters located at the sinusoidal or at the apical pole of the plasma membrane (PM) of hepatocytes.Emodin, 1, 3, 8-trihydroxy-6-methyl-anthraquinone, is an anthraquinone derivative from the roots of Rheum officinale Baill that has been widely used for the treatment of cholestatic hepatitis. It had pharmacological activities such as inhibitory activity of inflammation, anti-virus, anti-bacteria, immunosuppression, hepatoprotection and so on. So emodin may regulate expression of the transporter gene to relieve cholestasis. PARTâ… Protective efect of emodin on intrahepatic cholestasis in ratsObjective: To investigate the protective effect on acute intrahepatic cholestasis induced by alpha-naphthylisothiocyanate (ANIT) in rats.Methods: 32 SD rats were randomly divided into 4 groups: control group, emodin group without ANIT treatment, model group and emodin group with ANIT treatment. Before establishing the animal model, Emodin (40mg/kg/d) was intragastrically administrated to the rats in emodin group with and without ANIT treatment. Model and blank control were fed by sodium carboxymethylcellulose. All groups did not stop being administrated treating agent daily until executed. At the 5th day after administration and fasting for 4h, Model and emodin group with ANIT treatment were intragastrically administrated ANIT(100mg/kg) for modeling. Blank control and emodin group without ANIT treatment were fed by olive oil. At 48h after modeling, all rats were executed for taking specimens. Liver function and pathological changes of hepatic tissue were examined.Results: (1) In the model group compared with the normal control group,the concentrations of serum total bilirubin(TBiL), direct bilirubin (DBiL), alanine aminotransferase (ALT), aspartate aminotransferase (AST),alkaline phosphatase(ALP) and total bile acid(TBA) were increased(P<0.01); inflammatory cell infiltration,hepatic cellular change and necrosis could be observed by light microscop;(2) Compared to the model group, Emodin treatment resulted in significant reductions in TBiL, DBiL, ALT, AST, ALP and TBA (P<0.01 or P<0.05). By observing the liver pathology, it was found that hepatic cellular change and necrosis, inflammatory cell infiltration and bile duct proliferation were notably alleviated in emodin model with ANIT treatment. (3) In emodin group without ANIT treatment compared with the normal control group,the changes of Liver function and histopathology were not significant difference(P>0.05).Conclusion: Emodin remarkably could reduce the concentrations of serum TBiL, DBiL, ALT , AST , ALP and TBA,relieve the toxicity of bile acid and inhibit the hepatic injury. PARTâ…¡Effect of emodin on expression of transporter genes related to intrahepatic cholestasis of ratsObjective: To investigate the mechanism of emodin on acute intrahepatic cholestasis induced by alpha-naphthylisothiocyanate (ANIT) in rats.Methods: Acute cholestatic model in rats was induced by ANIT. Normal control group, emodin group without ANIT treatment, model group and emodin group with ANIT treatment were set up. Real-time fluorescent quantitative RT-PCR was used to detect the mRNA levels of the hepatic transport protein genes bile salt export pump (BSEP) , multidrug resistance-associated protein 2 (MRP2),Na+/taurocholate cotransporting peptide (NTCP),multidrug resistance protein 2 (MDR2),multidrug resistance protein 1a (Mdr1a), multidrug resistance protein 1b (Mdr1b), multidrug resistance-associated protein 3 (MRP3) and the nuclear receptor farnesoid X receptor (FXR). The expression of P-gp (P-glycoprotein) was determined by Western blotting analysis.Results: (1) In the model group compared with the normal control group, the genes expression of NTCP and FXR were down-regulated(P<0.01),the MDR2 , Mdr1b and MRP3 were up-regulated(P<0.01 or P<0.05).but the expression of BSEP,Mdr1a and MRP2 could not be affected(P>0.05).The expression of P-gp was increased (P<0.05). (2) Compared to the model group, Analysis of gene expression in livers from emodin-treated cholestatic rats revealed that NTCP, MRP3, Mdr1a, Mdr1b and MDR2 could be up-regulated (P<0.01 or P<0.05), but the expression of BSEP, FXR and MRP2 could not be affected(P>0.05). The expression of P-gp was increased in accordance with its mRNA (P<0.05) .(3) In emodin group without ANIT treatment compared with the normal control group,the changes of transporter genes were not significant difference(P>0.05).Conclusion: Emodin had a protective effect on hepatocytes and a restoring activity on cholestatic hepatitis. Mechanism of Emodin action on intrahepatic cholestasis may be related to induce expression of the bile-metabolism-related transporter MRP3 and P-gp in the liver to prevent bile acids and other toxic compounds overaccumulation in hepatocytes and hepatic toxicity.