Polyphenol-rich green tea extract induces thermogenesis in mice by a mechanism dependent on adiponectin signaling

Abstract

Adiponectin is downregulated in obesity negatively impacting the thermogenesis and impairing white fat browning. Despite the notable effects of green tea (GT) extract in the enhancement of thermogenesis, if its effects are being mediated by adiponectin has been scarcely explored. For this purpose, we investigated the role of adiponectin in the thermogenic actions of GT extract by using an adiponectin-knockout mice model. Male wild-type (WT) and knockout (AdipoKO) C57Bl/6 mice (3 months) were divided into 6 groups: mice fed a standard diet+gavage with water (SD WT, and SD AdipoKO), high-fat diet (HFD)+gavage with water (HFD WT, and HFD AdipoKO), and HFD + gavage with 500 mg/kg of body weight (BW) of GT extract (HFD + GT WT, and HFD + GT AdipoKO). After 20 weeks of experimentation, mice were euthanized and adipose tissue was properly removed. Our findings indicate that treatment with GT extract reversed complications of obesity in WT mice by decreasing final BW gain, adiposity index, adipocyte size and insulin resistance (IR). However, the action of the GT extract was not effective in reversing those markers in the AdipoKO mice, although GT acts independently in the reversal of IR. GT-treatment induced enhancement in energy expenditure (EE), BAT thermogenesis, and promoted browning phenotype in the subcutaneous WAT (scWAT) of WT mice. On the other hand, the thermogenic program was markedly impaired in BAT and scWAT of AdipoKO mice. Our outcomes unveiled adiponectin as a key direct signal for GT extract inducing adaptive thermogenesis and browning in scWAT.