微塑料经口暴露与消化系统肿瘤的潜在关联及毒性机制研究进展OA

Microplastics are ubiquitous environmental contaminants that enter human bodies mostly via oral ingestion,followed by accumulation and ectopic distribution in multiple digestive organs.Their potential tumor-promoting properties attract wide attention in toxicological research.The deposition and distribution patterns of microplastics within the human digestive tract,mucosal barrier translocation,tissue detection data of various digestive neoplasms,as well as toxic pathways linking microplastics to tumor initiation and progression are summarized in this review.Microplastics have been identified in gastrointestinal and liver tissue samples in accumulated studies,and most of the solid detection data was obtained from colorectal neoplasm specimens.In contrast,direct detection evidence in human pancreatic tissues remained limited,and most of the related conclusions were derived from animal and in vitro tests.So far,no definitive microplastic signals have been detected in human esophageal tissues,which is likely attributed to rapid food transit and short mucosal retention time.Multiple path-ways have been verified in in vivo and in vitro toxicological tests to mediate the promotive effects of microplastics on tumor initiation and progression,including the induction of oxidative stress,activation of chronic low-grade inflammation,destruction of intestinal barrier integrity and dysregulation of gut-target organ axes.Nevertheless,most of the current toxicological studies have used high-dose,short-term exposure models.Research on the health effects of long-term low-dose exposure under real-world conditions and on susceptible populations remains limited.Large-scale population-based epidemiological and cohort studies are needed to shed light on the association between environmental microplastic exposure and digestive system tumors.Toxicological and molecular mechanisms underlying the participation of microplastics in digestive tumorigenesis are elaborated in this review,and theoretical references are provided for carcinogenic risk evaluation of emerging environmental pollutants and subse-quent intervention exploration.