Early-life exposure to phthalates and nanoplastics alters gut microbiota and intestinal morphophysiology in rat dams and male offspring.

Phthalates and nanoplastics, common contaminants in everyday products and a result of their degradation, respectively, are linked to environmental degradation and human exposure. Research suggests that these substances can affect the gut microbiota and morphology, especially during pregnancy and lactation. Changes in the maternal microbiota can have lasting immunological and inflammatory effects on the offspring. This study investigated the effects of gestational (design 1) and gestational and lactational (design 2) exposure to a mixture of phthalates (PM) and nanoplastics (NPs), isolated or in combination, on colon histology and gut microbiota composition of directly exposed mothers (1), and of the male pups of these mothers (2). Pregnant Sprague Dawley rats were randomly divided into 4 groups: CTR (control; vehicle), PM (20 μg/kg/day of phthalate mixture), NPs (1 mg/kg/day nanoplastics NPs-100nm), PM+NPs (20 μg/kg/day PM + 1 mg/kg/day NPs-100nm). Treatment was administered orally from gestational day 5 (GD5) to GD20 for maternal fecal collection (design 1), or from GD10 to postnatal day 22 (PND22) for fecal collection from male pups (design 2). At the end of the treatment period, pregnant rats (GD20) and post-weaning male rats (PND22), 5-6 rats from each group, were euthanized. Colon samples and feces were collected for morphological and microbiome composition analysis, respectively. PM exposure increased goblet cells and reduced class and order Erysipelothichia/Erysipelotrichales at GD20, and reduced class and order Clostridia/Clostridiales at PND22. In addition, PM+NPs exposure increased goblet cells and class and order Bacilli/Lactobacillales and Gammaproteobacteria/Enterobacteriales at GD20. These findings provide evidence that exposure to PM+NPs during gestation affects the maternal microbiota and goblet cells; while this exposure during gestation and lactation causes alterations in the gut microbiota of the offspring, without histological changes. This may also provide information about the mechanistic effects of co-exposure in humans.