Gut-lung microbiota dynamics in mice exposed to Nanoplastics

Concern has grown over potential health effects of micro- and nanoplastics (M/NPs) exposure. There is significant interest in understanding their impact on animal and human microbiota due to its crucial role in preserving health, as research in this area is rapidly advancing. We conducted a sub-chronic exposure study involving 12 male mice, divided into two groups: a control group (n = 6) and a PET-NPs exposure group (n = 6). PET-NPs, administered by oral gavage at a dose of 0.5 mg/day in 0.1 ml/mice, were given daily for 28 days. Microbiota analyses were performed on lung, colon, oral cavity, and stool samples using 16S rRNA sequencing. Additionally, fecal short and medium-chain fatty acids were analyzed by GC/MS. No significant changes were observed in the fecal and oral microbiome of the treated mice, nor in the fecal fatty acid levels. However, there were prominent alterations in the colon, characterized by increased abundance of Gram-negative bacteria belonging to Veillonella and Prevotella genera, and of amino acid metabolism pathways, coupled with a decrease in Lactobacillus. PET-NPs ingestion caused unexpected alterations in the lung microbiome with an increase in the Pseudomonas and changes in microbial energy metabolism and nitrogen utilization. This study provides insights into the differential impact of PET-NPs exposure on various microbiome niches.