Co-exposure to lead and high-fat diet aggravates systemic inflammation in mice by altering gut microbiota and the LPS/TLR4 Pathway

Abstract This study reports the toxicity of Pb exposure on systemic inflammation in high-fat-diet (HFD) mice and the potential mechanisms. Results indicated that Pb exacerbated intestinal barrier damage and increased serum levels of lipopolysaccharide (LPS) and diamine oxidase in HFD mice. Elevated LPS activates the colonic and ileal LPS–TLR4 inflammatory signaling pathway and further induces hepatic and adipose inflammatory expression. The 16S rRNA gene sequencing results showed that Pb promoted the abundance of potentially harmful and LPS-producing bacteria such as Coriobacteriaceae_UCG-002, Alloprevotella, and Oscillibacter in the intestines of HFD mice, and their abundance was positively correlated with LPS levels. Additionally, Pb inhibited the abundance of the beneficial bacteria Akkermansia, resulting in lower levels of the metabolite short-chain fatty acids (SCFAs). Meanwhile, Pb inhibited adenosine 5′-monophosphate-activated protein kinase signaling-mediated lipid metabolism pathways, promoting hepatic lipid accumulation. The above results suggest that Pb exacerbates systemic inflammation and lipid disorders in HFD mice by altering the gut microbiota, intestinal barrier, and the mediation of metabolites LPS and SCFAs. Our study provides potential novel mechanisms of human health related to Pb-induced metabolic damage and offers new evidence for a comprehensive assessment of Pb risk.