[Comparation of Toxic Effect of Silicious Mineral Dusts on Lung Epithelial A549 Cells]

Considering the high contents of minerals and the potential health risk of mineral dusts to human and the environment, this paper was aimed to figure out the toxic effect and mechanism of four common mineral particles (quartz, albite, sericite, and montmorillonite). Cytotoxicity assays for cell viability (MTT assay), membrane integrity (LDH assay), oxidative stress (H₂O₂ assay) and inflammatory cytokines (TNF-α and IL-6 assay) were applied. The results showed the influence of these mineral particles on A549 cell viability followed the order of momtmorillonite > cericite≥quartz > albite. There was no obvious relation between cell viability and the content of SiO₂, however, good linear correlation with the content of iron, and the cytotoxicity of mineral dusts was strengthened with increasing iron content. Mineral dusts generated H₂O₂ in cell or cell-free systems. In particular, H₂O₂ exhibited a linear correlation with the iron content, which meant that iron in the mineral dusts played an important role in the generation of reactive radical. Among those samples, oxidative stress induced by montmorillonite was distinctly stronger, while there was negligible influence induced by quartz and albite. Besides, all the tested samples induced damage to A549 cell membrane, and triggered the release of TNF-α or IL-6, but differed by the kinds of mineral dusts. In conclusion, composition and structure directly affected, but were not the only factors that contributed to the biological activity of mineral dusts, the evaluation of cell viability, membrane damage, free radicals and inflammatory reaction induced by mineral dusts should take the external morphology, surface active groups, solubility, adsorption and ion exchange properties into consideration.