Bicyclol alleviates high-fat diet-induced hepatic ER stress- and autophagy-associated non-alcoholic fatty liver disease/non-alcoholic steatohepatitis in mice

Background and objective: Non-alcoholic fatty liver disease (NAFLD) is a manifestation of the metabolic syndrome in the liver, and non-alcoholic steatohepatitis (NASH) represents its advanced stage. Bicyclol has protective activity against NAFLD in mice; however, the effect of bicyclol on high-fat diet (HFD)-induced NASH and its underlying molecular mechanism remains unknown particularly anti-endoplasmic reticulum (ER) stress and autophagic machinery potentials. Therefore, the present study was performed to investigate the protective effect and underlying mechanisms of bicyclol action on NAFLD/NASH. Methods: Mice were fed an HFD to induce NAFLD/NASH, and bicyclol was administered as a treatment. Biochemistry and histopathological assays were performed to evaluate the effects of bicyclol on NAFLD/NASH. Moreover, the levels of hepatic ER stress- and autophagy-related markers were determined by western blotting. Results: The present results revealed that bicyclol exerted significant protective effects against HFD-induced NAFLD/NASH. This activity was evidenced by the decrease in elevated serum transaminase and hepatic triglyceride levels, and the attenuation of negative histopathological changes. Bicyclol considerably alleviated hepatic inflammation and apoptosis. The protein expression of ER stress-related markers, including C/EBP homologous protein (CHOP) and glucose-regulated protein 78 (GRP78), was downregulated by the bicyclol treatment in HFD-induced mice. However, the protein expression of autophagy-related markers (LC3 and Beclin 1) was upregulated by the treatment with bicyclol. Conclusion: Bicyclol protected HFD-induced NASH, and partly due to its ability of reducing ER stress and promoting autophagy.