Chlormequat chloride induces hepatic steatosis by promoting mTOR/SREBP1 mediated lipogenesis via AMPK inhibition

Abstract

Chlormequat chloride (CCC), a widely used plant growth regulator, is a choline analogue that has been shown to have endocrine-disrupting effects. Previous studies have shown that maternal exposure to CCC could induce hyperlipidemia and growth disruption in rat offspring. This study aims to further investigate the effects of peripubertal exposure to CCC on pubertal development and lipid homeostasis, as well as the underlying mechanisms. In vivo, male weanling rats were exposed to CCC (0, 20, 75 and 200 mg/kg bw/day) from post-natal day 21–60 via daily oral gavage. The results in rats showed that 75 mg/kg CCC treatment induced hepatic steatosis, predominantly microvesicular steatosis with a small amount of macrovesicular steatosis, in rat livers and 200 mg/kg CCC treatment induced liver damage including inflammatory infiltration, hepatic sinusoidal dilation and necrosis. In vitro, HepG2 cells were treated with CCC (0, 30, 60, 120, 240 and 480 μg/mL) for 24 h. And the results showed that CCC above 120 μg/mL induced an increase in triglyceride and neutral lipid levels of HepG2 cells. Mechanism exploration revealed that CCC treatment promoted the activation of mTOR/SREBP1 signalling pathway and inhibited activation of AMPK in both in vivo rat livers and in vitro HepG2 cells. Treatment with AMPK activator Acadesine (AICAR) could alleviate the lipid accumulation in HepG2 cells induced by CCC. Collectively, the present results indicate that CCC might induce hepatic steatosis by promoting mTOR/SREBP1 mediated lipogenesis via AMPK inhibition.