Autophagy is involved in acetylshikonin ameliorating non-alcoholic steatohepatitis through AMPK/mTOR pathway

Acetylshikonin (AS), a naphthoquinone constituent derived from Lithospermum erythrorhizon, has been revealed various pharmacological activities including anti-oxidative, anti-inflammatory and antifertility effects. Our previous study has illuminated the effects of AS on preventing obesity and hepatic steatosis in db/db mice. However, the effects of AS and the molecular mechanisms for curing non-alcoholic steatohepatitis (NASH) have not yet been studied. Autophagy has been considered as a lysosomal degradative pathway responsible for the removal of cellular lipid droplets through a process called lipophagy, which is recognized as a potential therapeutic approach for NASH. Here we hypothesize that autophagy is involved in the beneficial effects of AS on methionine-choline deficient (MCD) diet-induced NASH of mice. In this study, we observed that AS treatment ameliorated the pathological signs of NASH, and markedly suppressed the levels of hepatic IL-1 beta and TNF-alpha cytokines, and hepatocyte apoptotic cells in MCD diet-induced mice. Moreover, immunological analyses showed that the elevated expression of the fibrotic markers including alpha-SMA, collegen I, collegen III and fibronectin in MCD diet-induced mice were notably down-regulated by AS treatment. Nevertheless, the beneficial effects of AS on ameliorating NASH were notably counteracted by co-administration of chloroquine, an autophagy inhibitor. Furthermore, our data suggested that AS treatment increased hepatocyte autophagy in MCD diet induced mice via AMPK/mTOR pathway. These findings suggest that AS could be therapeutically effective in the development of NASH by ameliorating steatosis, inflammation, liver injury and fibrosis. (C) 2018 Elsevier Inc. All rights reserved.