The Study on Genotoxicity of PM_2.5 Mineral Dusts to A₅₄₉ Cells

Object: Detecting the influence of six main ingredients of PM_2.5 mineral dusts on the A₅₄₉ cell morphology, proliferation inhibition rate, micronuclei, and DNA damage to explore the genotoxicity of PM_2.5 mineral dusts.

Methods: (1) After exposure to six kinds of dusts of 200 μg mL⁻¹ concentration for 24 h, the morphology of A₅₄₉ cells was observed with Wright-Giemsa staining. (2) After exposure to different concentrations of mineral dusts for 24 h, the proliferation inhibition rate of A₅₄₉ cells was detected by MTT assay. (3) Cells were exposed to PM_2.5 mineral dusts at a concentration of 200 μg mL⁻¹ for 24 h. After Wright-Giemsa staining, the rates of micronucleus cells were counted under oil immersion lens. (4) Observe Comet phenomenon by single-cell gel electrophoresis (SCGE). The degree of DNA damage was observed by OTM.

Results: (1) Compared to the control group, membrane destruction, nuclear pyknosis, and mineral surface adhesion were mainly seen in the Sericite group and Albite group. In the Quartz group and Montmorillonite group, Cell gap grew bigger, which was loosely arranged and shrank gradually than control group, showing the absorption of a large number of minerals on the cell surface. (2) The proliferation inhibition rate of the six kinds of dusts to A₅₄₉ cells was (in descending order): KWC-M > Nano-SiO₂ > KWC-S > KWC-Q > KWC-A > KWC-C. The dust concentration was positively related to the inhibition of cell proliferation rate. (3) As the dusts’ concentration increased, the incidence of micronuclei gradually increased. The rate was positively correlated to exposure concentration. (4) The six mineral dusts can damage DNA of the A₅₄₉ cells by dose–response relationship. The higher concentration of the mineral dusts was, the more obvious the DNA damage became.

Conclusion: The six main ingredients of the PM_2.5 mineral dusts can change A₅₄₉ cell morphology in different degrees, improve proliferation inhibition rate of the cells, increase the number of micronuclei cells, and damage DNA. Then we come to the conclusion that PM_2.5 mineral dusts can change the genotoxicity of the cells possibly.