Influences of PM_2.5 on gut physiology, microbiota and metabolites

PM_2.5 (fine particulate matter) has become a significant contributor to global health risks. Emerging evidence links PM_2.5 exposure to chronic diseases via gut-mediated pathways, including systemic inflammation and oxidative stress. These processes disrupt intestinal barrier integrity (e.g., reducing occluding and ZO-1 expression) and increase intestinal permeability, facilitating harmful substance translocation within the organism. Crucially, PM_2.5 exposure significantly alters gut microbiota composition: increasing Lactobacillus, Parabacteroides, Firmicutes and Akkermansia abundance, while decreasing Bacteroidetes and short-chain fatty acid (SCFA)-producing bacteria (e.g., Prevotella). Concomitant metabolite disturbances feature impaired SCFA synthesis and phosphatidylcholine metabolic dysregulation. These microbiota and metabolite shift collectively impair gut-brain axis function. Therefore, enhanced PM_2.5 pollution control is vital for gut health maintenance and disease prevention. This review summarizes the impact of PM_2.5 on gut structure, microbiota, metabolites and their mechanistic links to systemic health.