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Nanoparticles (NPs) is used in dentistry to give certain materials desired properties, such as grinding effect in toothpaste or to change viscosity in nanocomposite, but also occurs naturally. NPs are defined as particles ranging from 1 nm to 100 nm in one dimension1. Use of nanomaterials improves properties of materials, but the potential for adverse effects are still unknown. Research indicates that NPs are able to cross the blood-brain barrier and locate in the central nervous system1, 2. Possible neurotoxic effects are investigated in this in vitro study.

Aims of this study:
• Identify and describe effects of NPs on cell morphology in PC12 cells
• Establish dose-response relationship between NP concentration and cell death
• Study the potential of NPs to induce oxidative stress and generate cellular ROS
• Quantify differences in toxic potential of NPs of different size
• Compare the effects of similar exposure in two different batches of the same cell line

Methods

PC12 cells are a cancer cell line collected from the adrenal glands of Brown rat (Rattus norvegicus) with neuron-like structure. Cells were exposed to silica NPs of different concentrations and sizes (10 nm and 50 nm). Flow cytometer (ROS), MTT-assay (cell viability), Western blotting (protein expression), HOECHST/PI staining (apoptosis, necrosis) and neurite outgrowth kit, light, – confocal and phase contrast microscopy were used.

Results

• Differences in cell morphology were observed in samples exposed to NPs. Needlelike structures were seen.
• Lower cell viability was seen in cells exposed to higher concentrations of NPs of both sizes. SiNP10 seem to be less harmful to the cells than SiNP50.
• Oxidative stress and ROS seems to be increasing equivalent with increasing NP concentration.
• NPs size and varying concentrations seems to be important factors in cell survival, apoptosis/necrosis, ROS and oxidative stress formation and changes in cell morphology
• Differences were seen between the two cell batches i. e differentiation and differences in adhesiveness.


 


References

Feng, X., Chen, A., Zhang, Y., Wang, J., Shao, L., & Wei, L. (2015).
International Journal of Nanomedicine, 10, 3547-3565. doi:10.2147/IJN.S79892

Wang, F., Jiao, C., Liu, J., Yuan, H., Lan, M., & Gao, F. (2011). Toxicology in Vitro, 25(8),
1548-1556. doi:https://doi.org/10.1016/j.tiv.2011.05.019