Green tea polyphenols positively impact hepatic metabolism of adiponectin-knockout lean mice

Green tea (GT) has health benefits but the mechanism of its biological effects remains poorly known. Adiponectin has been considered a key adipocytokine for protection against hepatic lipid accumulation. We aimed to assess whether the effects of GT on hepatic lipid metabolism are mediated by adiponectin. For this purpose, we used wild-type lean mice and adiponectin-knockout mice fed with a standard diet and treated with 500 mg/kg of GT extract for 12 weeks. Adiponectin knockout mice had a slight increase in adiposity, and lipid synthesis while an impairment in insulin signaling. These effects were mitigated by GT supplementation independently of adiponectin. GT supplementation was able to stimulate energy expenditure, and oxidative lipid pathways (AdipoR2, SIRT1, AMPK and UCP2 expression) in an adiponectin independent-manner. These results indicate that the hepatoprotective effect of GT against lipid accumulation in non-alcoholic fatty liver disease can be partially mediated by adiponectin.