Polystyrene microplastics induce endoplasmic reticulum stress, apoptosis and inflammation by disrupting the gut microbiota in carp intestines

Microplastics have been recognized as a widespread new pollutant in nature and have induced an increase in the occurrence of a variety of diseases in carp. An animal model of microplastic ingestion was successfully established in an aqueous environment. The gut microbiota was analysed using a metagenomic approach. The results showed a significant reduction in the relative abundances of Lactococcus garvieae, Bacteroides_paurosaccharolyticus, and Romboutsia_ilealis after PS-MPs treatment. The 16S Silva database was used to predict and analyse the known genes. Intestinal flora disorders related to infectious diseases, cancers, neurodegenerative diseases, endocrine and metabolic diseases, cardiovascular diseases, and other diseases were found. The intake of PS-MPs resulted in damage to carp intestinal tissue and apoptosis of intestinal epithelial cells. The levels of the inflammatory cytokines IL-1 beta, IL-6, and TNF-alpha were significantly increased with the intake of PS-MPs. The gene and protein levels of GRP78, Caspase-3, Caspase-7, Caspase-9, Caspase-12, PERK, IRE1, and ATF6 were further examined in PS group. The occurrence of ERS and apoptosis in carp intestines was confirmed. These results suggest that the accumulation of PS-MPs in the aquatic environment can disturb the carp gut microbiota and induce ERS, apoptosis, and inflammation in the intestinal tissue.

Automated summary

Microplastics have been identified as a widespread pollutant in nature, causing various diseases in carp. A model of microplastic ingestion was successfully established, and the gut microbiota was analyzed. The results showed a reduction in specific bacteria after treatment with PS-MPs, and related intestinal flora disorders were found. Ingestion of PS-MPs resulted in intestinal tissue damage, apoptosis, and increased inflammation. The occurrence of ERS and apoptosis in carp intestines was confirmed. These findings indicate that the accumulation of PS-MPs in the aquatic environment can disrupt the carp gut microbiota and induce ERS, apoptosis, and inflammation in the intestinal tissue.