Developmental toxicity and cytotoxic/genotoxic potential of PM₁₀ rural extracts using Xenopus laevis embryos and A549...

Airborne particulate matter is increasingly recognized as a hazard for developmental health. While epidemiological studies associate PM₁₀ prenatal exposure and adverse outcomes (including low birth weight and preterm birth), experimental evidence clarifying biological plausibility remains limited, especially for complex PM mixtures collected in non-urban settings. Air-quality-related developmental risks in rural areas interested by PM pollutions are underestimated. In this context, our study aimed to assess the developmental toxicity of PM₁₀ extracts collected at a rural Po Valley site, using a sensitive vertebrate embryo model. We exposed Xenopus laevis embryos to extracts of daytime and nighttime PM₁₀ collected over two weeks (March 2022) and evaluated lethality, teratogenicity and developmental progression with the Refined Frog Embryo Teratogenesis Assay-Xenopus (R-FETAX). In parallel, PM₁₀ filters were chemically characterized (mass, major ions, carbon fractions, and multiple elements), allowing us to model links between developmental outcomes and specific PM components. To provide a conventional toxicological benchmark, extracts were also tested in A549 human lung epithelial cells for cytotoxicity and genotoxicity. Our results show that, despite the absence of lethality or gross malformations, some PM₁₀ extracts induced statistically significant developmental delays. Modelling revealed correlations between delays and PM₁₀ mass as well as several measured analytes, with Zn and Cu displaying the clearest dose-dependent associations. Embryonic development detected subtle effects of low-level PM₁₀ exposure that were not captured by standard cytotoxicity/genotoxicity endpoints in A549 cells under the tested conditions. Collectively, these findings support the utility of a developmental model for mixture-based particulate toxicology evaluation.