Analysis of cytotoxicity and genotoxicity in a short-term dependent manner induced by a new titanium dioxide nanoparticle in murine fibroblast cells

Abstract

The extensive use of titanium dioxide nanoparticles (TiO₂ NPs) in cosmetics, food, personal care products, and industries brought concerns about their possible harmful effects. Nowadays it has become important to assess TiO₂ NPs toxic effects as a way to understand their primary risks. In the cellular environment, after cell uptake, TiO₂ NPs were described to induce reactive oxygen species (ROS) production, unbalance oxidative state, and activate apoptosis in several cell lines. Therefore, we aimed to evaluate the cytotoxicity and genotoxicity of a new TiO₂ NP surface-functionalized with sodium carboxylic ligands in a murine fibroblast cell line (LA-9). TEM and DLS analyses were performed to define nanoparticle physicochemical characteristics. We evaluated the metabolic activity and LDH released after 24 h exposition to determine cytotoxic effects. Also, we evaluated DNA damage, intracellular reactive oxygen species (ROS) production, and apoptosis induction after 24 h exposure. The TiO₂ NP impaired the cell membrane integrity at 1000 μg/mL, induced intracellular ROS production and late apoptosis at 24 h. The genotoxic effects were observed at all conditions tested at 24 h. Indeed, in fibroblasts exposed at 100 μg/mL was observed early apoptosis cells. The intracellular ROS content was increased in a dose-dependent manner. Thus, short-term exposure to TiO₂ NP promoted cytotoxicity, genotoxicity and activated apoptosis pathways based on the potential role of oxygen species in the fibroblasts cell line.

Keywords:

• Nanomaterials
• titanium dioxide nanoparticle
• cytotoxicity
• genotoxicity
• oxidative stress
• apoptosis

Acknowledgments

The authors acknowledge the PETROBRAS for all financial support during the work execution. M.P., A.C.M.F. and P.B. were grateful respectively to PETROBRAS Masters, PhD and post-doctoral fellowships. We thank the Post-Graduation Program of Evolutionary Genetics and Molecular Biology from UFSCar, Prof. Dr. Marcos Roberto Chiaratti (UFSCar) and Prof. Dra. Marisa Narciso Fernandes (UFSCar) for kindly providing technical assistance in Comet assay analysis, and Prof. Dr. Valtencir Zucolotto (USP) for providing all the assistance for DLS analysis. We also thank all the Nano-PETROBRAS project team members who assisted indirectly to this work. We also acknowledge Fundação de Amparo à Pesquisa do Estado de São Paulo - FAPESP (2013/07296-2), FINEP, Conselho Nacional de Desenvolvimento Científico e Tecnológico – CNPq (166281/2017-4), Financiadora de Estudos e Projetos – FINEP, and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – CAPES (001).

Disclosure statement

No potential conflict of interest was reported by the author(s).