In Vitro Cytotoxicity Of Several Typical Mineral Particles On Human Lung Epithelial Cell

In this paper, the chemical composition, phase, structure andmorphology of Nano-SiO2and several mineral samples (quartz (KWC-Q4, KWC-Q3), calcite (KWC-C4, KWC-C3), sericite (KWC-S4,KWC-S3), albite (KWC-A4, KWC-A3)， montmorillonite (KWC-M))were analysised by the methods of XRF, XRD, IR, SEM, andelectrochemistry test. The effects of mineral particles on cell viability,morphology, cell membrane damage, metabolic capability, redox systemand immune system change of A549cells were studied by methods ofMTT, Wright–Giemsa dye, and SEM. Cell genetic toxicity of mineralparticles was tested and assessed by micronucleus experiment andSingle cell gel electrophoresis test in vitro. Finally, the toxicit ymechanism of mineral particles to A549cells was discussed.The research results show that, the influence of calcite and albiteon the cell viability was not obvious. Compared with the control group,there was no significant difference in the cell death rate with theincrease of the exposure concentration after24h. But, the cell deathrate significantly increased when the exposure time was48h. The cellviability significantly increased with the increase of the exposureconcentration and rendered well dose effect relationship after24h. Thetoxic effe ct of montmorillonite and Nano-SiO2to A549cell was high,their cell survival rate of A549cell was (53.22±7.94)%and(73.76±2.72)%respectively when the exposure concentration was50μg/mL. The survival rate of A549cell was falling sharply with theincrease of the exposure concentration, and then tended stability at20%when the exposure concentration was200μg/ml. The addition ofmineral particle caused diffe rent degrees change of pH a nd S of c ellculture medium. The pH of calcite, quartz, Nano-SiO2, and albitesuspension were stabilized at7.15,7.65,7.66and7.35respectivelyafter48h, while the pH of sericite and montmorill onite suspensionreduced constantly. The calcite did not cause the amount of LDH release of A549cell, but it presented a dose-effect relationship betweenquantity and concentration in the rest of the group. The release a mountof LDH： Nano-SiO2> KWC-M> KWC-Q4> KWC-Q3> KWC-S3>KWC-S4> KWC-A4> KWC-A3. There was no significant differencewith calcite, albite and sericite to SOD activit y change in A549cell.The calcite and sericite cause the decrease of GSH, while the albite cancause the increase. Quartz and montmorillonite can cause increase ofSOD activity in A549cell and present a dose-effe ct relationship, whilecompared with negative control group, the content of GSH increased.Nano-SiO2can cause marked increase of SOD activity and decrease ofGSH. Compared with control group, TNF-α increased significantly afterincubation with mineral suspension at200μg/mL for3hours, allmineral particles can promoye the TNF-α secretion of A549cell. Thecalcite and calcite exposure did not cause the increase of IL-6in A549cell, while other particles triggered the inflammatory reaction. Allmineral particle tested can cause the increase of cell micronucleus rateand present a dose-effect relationship when the cell death rate is lowertthan some extent except mont morillonite. Micronucleus rate of A549cells listed as: Nano-SiO2> KWC-Q3> KWC-S4> KWC-C4>KWC-S3> KWC-A4> KWC-Q4> KWC-A3> KWC-C3. The results ofsingle cell gel electrophoresis experi ment showed the DNA toxicity ofall particles are below the2nd damage level, the DNA damage:KWC-M> Nano-SiO2> KWC-S3> KWC-S4> KWC-Q4> KWC-Q3>KWC-C3> KWC-A4> KWC-A3> KWC-C3.