Hepatoprotective effect of curcumin against bisphenol A-induced hepatic steatosis via modulating gut microbiota dysbiosis and related gut-liver axis activation in CD-1 mice

Chronic exposure to low-dose bisphenol A (BPA) has become a global problem of public health. Our previous work showed that low-dose BPA exposure caused gut microbial dysbiosis and hepatic steatosis. Curcumin, a polyphenol extracted from turmeric, has an inhibitory effect on liver lipid accumulation, whether curcumin can alleviate BPA-induced hepatic steatosis through improving intestinal flora and modulating gut-liver axis remains to be elucidated. Male CD-1 mice were fed with BPA-contaminated diet supplemented with or not with curcumin for 24 weeks. Curcumin supplementation markedly ameliorated liver fat accumulation and hepatic steatosis induced by BPA. Gut microbiota analysis via 16S rRNA sequencing revealed that the relative abundance of Proteobacteria and Firmicutes/Bacteroidetes ratio were increased in BPA-fed mice, and this alteration was reversed by curcumin treatment. Akkermansia, which was recognized as a potential probiotic, was significantly reduced after BPA exposure and was restored to the control level with curcumin addition. Furthermore, curcumin supplementation reversed the down-regulation of intestinal tight junction protein expressions (zona occludens-1 and occludin), improved increased gut permeability, reduced serum lipopolysaccharide level and suppressed the activation of hepatic toll-like receptor 4 / nuclear factor-κB (TLR4/NF-κB) pathway induced by BPA. These results indicated that the protective effect of curcumin against hepatic steatosis induced by BPA and further revealed that its mechanism might be its prebiotic effect on maintaining intestinal flora homeostasis and improving intestinal barrier function, consequently reducing serum lipopolysaccharide-triggered inflammatory response in the liver. Our work provides evidence for curcumin as a potential nutritional therapy for BPA-mediated hepatic steatosis.