Exercise improves lipid droplet metabolism disorder through activation of AMPK-mediated lipophagy in NAFLD

AIM: To emphasize the mechanism of the effect of exercise on lipid droplet (LD) metabolism disorder in nonalcoholic fatty liver disease (NAFLD). MAIN METHODS: C57BL/6J mice were randomly divided into three groups: The first group was fed with a normal diet (CON), the second group was fed a high-fat diet (HF), and finally group with a high-fat diet intervention and swim training (HF-EX). The total intervention period was 16 weeks. RT-PCR and Western blot were performed to evaluate the effect of exercise on LDs metabolism and the AMPK pathway. Histopathological examinations and immunofluorescence were performed to evaluate the lipid deposition and lipophagy in the liver. KEY FINDINGS: Exercise reduced liver steatosis and insulin resistance along with the stimulation of AMPK/SIRT1 signaling and downstream regulation of lipid metabolism. In addition, exercise increased the expression of autophagy marker and colocalization of LC3 and LAMP1 with LDs. SIGNIFICANCE: Exercise stimulated AMPK/SIRT1 and activated lipophagy in NAFLD. Enhancing lipophagy may be one of the key mechanisms of regulation and resolution of NAFLD by exercise.