Tectorigenin alleviates intrahepatic cholestasis by inhibiting hepatic
inflammation and bile accumulation via activation of PPARg
Abstract
Background and purpose: Increasing evidence has shown that human
cholestasis is closely related to hepatic macrophage accumulation and
activation. Research has indicated that peroxisome
proliferator-activated receptor-g (PPARg) activation exerts liver
protection in cholestatic liver disease (CLD), particularly by
ameliorating inflammation and fibrosis, thus limiting disease
progression. However, existing PPARg agonists, such as troglitazone and
rosiglitazone, have significant side effects that impede their clinical
application in the treatment of CLD. In this study, we found that
tectorigenin (TEC) can alleviate intrahepatic cholestasis in mice by
activating PPARg. Experimental approach: Wild-type mice received
intragastric administration of a-naphthylisothiocyanate (ANIT) or were
fed a diet containing 0.1% 3,5-diethoxycarbonyl-1,4-dihydrocollidine
(DDC) to establish an experimental intrahepatic cholestasis model and
TEC intervention simultaneously, followed by determination of
intrahepatic cholestasis and the involved mechanisms. In addition, PPARg
deficient mice were administered ANIT and/or TEC to determine whether
TEC exerts its liver protection effect by activating PPARg. Key results:
Our results demonstrated that TEC intervention alleviated intrahepatic
cholestasis by inhibiting hepatic macrophage recruitment and activation
as well as promoting the expression of bile transporters through
activating PPARg. Furthermore, our results show that TEC increased bile
salt export pump (Bsep) expression through enhanced PPARg binding to the
Bsep promoter. We also demonstrated that PPARg deficiency blocked the
hepatocyte protective effect of TEC during cholestasis. Conclusions and
implications: In conclusion, TEC reduced hepatic macrophage recruitment
and activation, and enhanced bile acid export by activating PPARg. Taken
together, our results suggest that TEC is a potential drug for the
prevention of CLD.