Quantitative evaluation of microplastic interference with gut microbiota: Identifying sensitive indicators and key factors

Microplastics (MPs), as pervasive pollutants with widespread distribution and persistent presence, primarily accumulate in the gastrointestinal tract and disrupt gut microbiota. However, the sensitive indicators that signal MPs interference with gut microbiota, such as diversity indices, microbiota composition, and key exposure characteristics like MPs features and exposure conditions, remain unclear. This study proposes a data-driven framework aimed at integrating and harnessing literature-derived data through meta-analysis, combined with machine learning models to quantitatively evaluate the impact of MPs on gut microbiota. The findings indicate that the Shannon index, abundance of Firmicutes, Bacteroidetes, and Actinobacteria, and the ratio of Firmicutes to Bacteroidetes (F/B), exhibit significant responses to MPs exposure. Notably, the F/B ratio is the most sensitive indicator for MPs interference with gut microbiota. Furthermore, the exposure concentration, size, and duration of MPs were identified as the key factors affecting the F/B ratio. Based on these key factors, we established a quantitative model evaluating the variation of the F/B ratio with robust predictive ability (R² = 0.91). In summary, this study identified a sensitive biomarker and key influencing factors of MPs-induced disruption of gut microbiota, offering novel insights and technical support for evaluating gastrointestinal adverse effects associated with MPs pollution.