From insects to mammals! Tissue accumulation and transgenerational transfer of micro/nano-plastics through the food chain.

Despite extensive global attention on microplastic pollution, our understanding of the pathways underlying microplastic translocation, accumulation, and their potential impacts on ecosystems and human health through the food chain remains incomplete. To investigate the translocation and accumulation of microplastics from insects to mammals, we developed a novel oral exposure model that Tenebrio molitor larvae (yellow mealworms, invertebrate terrestrial insects) were firstly orally exposed to both micro and nanometer-sized plastics (M/NPs), and subsequently fed as a food source to mice (mammals). Our results provide clear evidence that micro/nanoplastics (M/NPs) do indeed translocate through the food chain, from lower to higher trophic levels. Fluorescence microscopy and tissue quantification revealed the accumulation of M/NPs in the digestive, somatic, and circulatory systems of the larvae. Specifically, the food chain transferred M/NPs were later detected in the digestive, respiratory, and urinary systems of mice, showcasing strong fluorescent signals in vital organs such as the lungs, liver, intestines, brain, and kidneys, as well as in embryos. These findings highlight the intricate dynamics of M/NPs contamination, emphasizing their ability to traverse biological barriers, accumulate in organisms, and potentially impact embryonic development via food chain transfer.