Defensive remodeling of gut microbiota under microplastic stress and its pathogenic mechanism

Owing to their low cost and durability, microplastics (MPs) are widely used in daily life. However, with their massive emissions, environmental pollution has become increasingly severe. MPs can enter organisms via inhalation, gastrointestinal ingestion, and dermal contact, accumulate in higher trophic-level organisms through the food chain, impair intestinal barrier function, disrupt immune regulation, and alter the structure of the gut microbiota, thereby causing significant harm to the host. The gut microbiota is intrinsically linked to host health and serves as a crucial indicator for toxicity assessment. Therefore, understanding the response of gut microbiota to microplastic exposure is of paramount importance. This review comprehensively examines the impacts of MPs on the gut microbiota across animal models-a subject of widespread global concern. It elaborates on the significance of the gut microbiota and the cascade reactions triggered by microplastic exposure, including metabolic disorders, oxidative stress, and dysbiosis. Subsequently, it discusses the protective mechanisms of the gut microbiota against microplastic stress and the current state of research in this field, both domestically and internationally. Finally, prospects and recommendations for future research on MPs and gut microbiota are proposed. This review provides theoretical support for investigating the relationship between microplastic-induced alterations in gut microbiota and disease pathogenesis, as well as for developing therapeutic strategies. It also provides insights into the underlying mechanisms of interaction between gut microbiota and MPs.