Effect of titanium dioxide nanoparticles on DNA methylation of human peripheral blood mononuclear cells

Mohammad Malakootian; Alireza Nasiri; Alvaro R Osornio-Vargas; Maryam Faraji

doi:10.1093/toxres/tfab085

Effect of titanium dioxide nanoparticles on DNA methylation of human peripheral blood mononuclear cells

Toxicol Res (Camb). 2021 Aug 31;10(5):1045-1051. doi: 10.1093/toxres/tfab085. eCollection 2021 Oct.

Authors

Mohammad Malakootian¹, Alireza Nasiri¹, Alvaro R Osornio-Vargas², Maryam Faraji¹

Affiliations

¹ Environmental Health Engineering Research Center, Kerman University of Medical Sciences, Kerman, Iran.
² Department of Pediatrics, University of Alberta, 3-591 Edmonton Clinic Health Academy, Edmonton T6G 1C9, Canada.

Abstract

The aim of the current study was to investigate the effect of well-characterized TiO₂ nanoparticles on DNA methylation of peripheral blood mononuclear cells (PBMCs) in vitro. Maximum non-toxic concentration of nanoparticles for PBMCs was determined by MTT assay. The effect of TiO₂ nanoparticles at concentrations of 25-100 μg/ml on DNA methylation of PBMCs was investigated by measuring the %5-mC alterations through an ELISA assay. The physicochemical analysis showed that the TiO₂ nanoparticles were crystalline, pure and in the anatase phase. Peaks related to Ti-O tensile vibrations were observed in the range of 1510 cm^-1. The size of nanoparticles was in the range of 39-74 nm with an average hydrodynamic diameter of 43.82 nm. According to the results of the MTT test, 100 μg/ml was found to be maximum non-toxic concentration. The %5-mC in treated PBMCs revealed that TiO₂ nanoparticles could lead to DNA hypomethylation in PBMCs. The %5-mC difference compared with the negative control was found to be 2.07 ± 1.02% (P = 0.03). The difference of %5-mC between the 25 and 100 μg/ml concentration of nanoparticles was statistically significant (P = 0.02). The results of the current study show that the TiO₂ nanoparticles cause DNA hypomethylation in PBMCs in a dose-response manner. Therefore, it is recommended to evaluate the effects of cytotoxicity and epigenotoxicity of commonly used nanoparticles before their use.

Keywords: DNA methylation; epigenetic genotoxicity; titanium dioxide nanoparticles.