The toxicity of nano polyethylene terephthalate to mice: Intestinal obstruction, growth retardant, gut microbiota dysbiosis and lipid metabolism disorders.

Polyethylene terephthalate (PET) are widely used in our daily life while they may be broken to smaller fractions as nano-sized PET (nPET) in the environment. The toxicity of nPET is still less studied. This work first evaluated the LD50 of different size of nPET (200 nm, S-nPET; 700 nm, B-nPET) in mice, then studied the health effects of single exposure to S/B-nPET at 200 mg/kg bw for 30 days. It was found that the LD50 was 266 mg/kg bw for S-nPET and 523 mg/kg bw for B-nPET, respectively, showing a size-dependent effect. S-nPET caused weight loss, cyst, intestinal obstruction, organ damage and mortality (40%), and perturbed gut microbiome and metabolome especially lipid metabolism, such as upregulated cholesterol, glycocholic, propionic acid, niacinamide, ectoine and xanthine, and downregulated arachidonic acid, anserine, histamine, while B-nPET did not. Serological analysis found S-nPET brought more lipid metabolic immune and neurological damage than B-nPET, confirming the size-dependent effect. To the best of our knowledge, this is the first report on the systematic toxicity of nPET to mice. Further studies are warranted for life-long effects of nPET. The protocol applied in this work may also be used for the study of the health effects of other plastics.