Effect And Mechanism Of Fenofibrate On Intrahepatic Cholestasis Induced By ANIT

Objective:Alpha-naphthylisothiocyanate(ANIT)is the most widely used experimental chemical to imitate human intrahepatic cholestasis for investigations of the pathogenesis and pharmacological mechanisms of cholestatic liver disease.Fenofibrate,a PPAR? agonist,is the most widely prescribed drug for the treatment of hyperlipidemia.Although fibrate drugs were reported to be beneficial for cholestasis,the underlying mechanism has not been determined.Methods:The wild-type mice were divided into 8 groups(n = 5),vehicle/control(WT-C),ANIT/control(WT-A),ANIT/fenofibrate 5,25 and 125 mg/kg(WT-A-F5,WT-A-F25,WT-A-F125),fenofibrate 5,25 and 125 mg/kg twice a day(WT-F5,WT-F25,WT-F125).Considering that fenofibrate 25 mg/kg twice a day was found to totally inhibit the toxic responses,the Ppara-null mice were divided into 4 groups(n = 5),vehicle/control(KO-C),ANIT/control(KO-A),ANIT/fenofibrate 25 mg/kg twice a day(KO-A-F25),fenofibrate 25 mg/kg twice a day(KO-F25).Fenofibrate was dissolved in corn oil and administered by oral gavage twice daily for 5 days.A single dose of ANIT 75 mg/kg in corn oil was administered to the indicated groups on day 4.To demonstrate the role of PPAR?,4 groups of wild-type mice,vehicle/control(WT-C),ANIT/control(WT-A),ANIT/WY-14643(WT-A-WY),and WY14643(WT-WY)were designed for WY-14643 experiment.WT-A-WY and WY14643 groups fed a diet containing 0.1%(w/w)WY14643 for 5 days.A single dose of ANIT 75 mg/kg in corn oil was administered to the indicated groups on day 4.To explorer the role of the JNK pathway,wild-type mice were treated with non-selective JNK pathway inhibitor SP600125.Specifically,4 groups wild-type mice(n=5),vehicle/control(WT-C),ANIT/control(WT-A),ANIT/SP600125 15 mg/kg(WT-A-SP),SP600125 15 mg/kg(WT-SP)were included in this experiment.To confirm whether incompletely inhibited JNK signaling was less effectiveness with overdose of fenofibrate,another 4 groups of wild-type mice,vehicle/control(WT-C),ANIT/control(WT-A),ANIT/fenofibrate 125 mg/kg twice a day(WT-A-F125),and ANIT/fenofibrate 125mg/kg/SP600125(WTA-F-SP)were used in the present study.SP600125 was dissolved in corn oil and administered by intraperitoneal injection once daily.Two hours after the first dose of SP600125,a single dose of ANIT 75 mg/kg was administered to the indicated groups.Forty-eight hours after the ANIT administration,the mice were weighed and killed by asphyxiation using carbon dioxide following blood collection.Results:Fenofibrate 25 mg/kg twice a day totally attenuated ANIT-induced cholestasis and liver injury as indicated by biochemical and histological examination.This protection occurred in wild-type mice but not in Ppara-null mice.Alterations in bile acid synthesis and transport were found to be an adaptive response rather than direct regulation by fenofibrate.WY14643 attenuated ANIT-induced cholestasis and liver injury coincident with inhibition of the JNK signaling.Although cholestasis was not affected,liver injury in ANIT model and unprotected group was potently inhibited by SP600125.Conculsions:Taken together,the present study suggested that fenofibrate could effectively suppress cholestatic liver injury induced by ANIT.The protection occurred via inhibition of the JNK pathway.The dose-response relationship and dependence on PPAR? in the protection provides an important basis for clinical investigation of cholestasis treatment using fenofibrate.This widening of the pharmacological mechanisms to fenofibrate protection against intrahepatic cholestasis offers further therapeutic opportunities for cholestatic liver diseases.