Chronic Exposure to 2,3,7,8-Tetrachlorodibenzofuran Induces Obesogenic Effects on Mice Fed Normal or Western Diets

2,3,7,8-Tetrachlorodibenzofuran (TCDF), a widespread, typical persistent organic pollutant, accumulates mainly in liver and adipose tissues. However, the effects of chronic exposure to environmentally relevant doses of TCDF on adipose tissues and obesity remain elusive. This study revealed that adult mice exposed to 0.3 or 3 μg/kg of TCDF for 16 weeks developed mild adiposity under normal chow diets in a dose-dependent manner, which was evidenced by significant accumulation of epididymal white adipose tissues (eWAT) and inguinal white adipose tissues (iWAT). Interestingly, the obesogenic effects of TCDF were dose-independent under western diets; low-dose TCDF exposure caused a more pronounced obesogenic effect and associated metabolic disorders. Consistent with the obesogenic effect, TCDF was further revealed to interfere with adipogenesis, lipogenesis, and thermogenesis in eWAT or iWAT. Moreover, our results pointed out that TCDF plays roles in obesity through AhR-dependent and AhR-independent manners. Taken together, these results showed the obesogenic effect of environmentally relevant doses of TCDF and elucidated that TCDF caused dysfunction of adipose tissues, which strongly supports that TCDF is an environmental obesogen and that more attention should be paid to the health risks of TCDF regarding obesity.