Exposure to dibutyl phthalate impairs lipid metabolism and causes inflammation via disturbing microbiota-related gut-liver axis

Abstract

Dibutyl phthalate (DBP), a kind of typical environmental pollutant, is widely used as plasticizers, and its neurotoxicity and developmental toxicity have been found in recent years. However, whether oral DBP exposure will affect the homeostasis of gut microbiota and its adverse response in liver of mammalians remain unclear. In the present study, 10-week experimental cycles of vehicle or DBP (0.1 and 1 mg/kg) were given to 6-week-old C57BL/6J mice by oral gavage. Our results revealed that the body weight of mice was increased after exposure to both low and high doses of DBP. The serum levels of hepatic triglyceride and total cholesterol were significantly increased in response to both doses of DBP. In addition, some pivotal genes related to lipogenesis were also increased in liver at the mRNA level. Evaluation of gut microbiota by 16S rRNA sequencing technology showed that 0.1 mg/kg DBP exposure significantly affected gut microbiota at the phylum and genus levels. Moreover, DBP exposure decreased mucus secretion and caused inflammation in the gut, leading to the impairment of intestinal barrier function. Exposure to DBP inhibited the expression of peroxisome proliferator-activated receptor-γand activated the expression of nuclear factor kappa B. In addition, DBP exposure increased the level of lipopolysaccharide in serum, and increased the expression of toll-like receptor 4 and the levels of inflammatory cytokines, such as interleukin (IL)-1β, IL-6, and tumor necrosis factor alpha, in the liver. These results indicated that exposure to DBP disturbed the homeostasis of gut microbiota, induced hepatic lipid metabolism disorder, and caused liver inflammation in mice via the related gut-liver axis signaling pathways.