Chromosomal aberrations and changes in the methylation patterns of Lactuca sativa L. (Asteraceae) exposed to carbon nanotubes

Carbon nanotubes (CNTs) are one of the most important nanomaterials, with applications in several areas. The exponential increase in the production and use of CNTs, however, increases the likelihood of their release into the environment and potential impacts on environmental systems. We evaluated the cytogenotoxic potential of carboxylated multi-walled carbon nanotubes (MWCNT-COOH) as well as its influence in the methylation patterns of Lactuca sativa meristematic cells. Root elongation was observed at concentrations of 1.0; 10.0; 50.0 and 100.0 mu g/mL, and decreased seed germination at the highest concentration evaluated (100.0 mu g/mL). Cytogenetic analysis revealed that MWCNT-COOH induced increases in the chromosomal aberration index and micronucleus frequency. Accumulations of cells in the sub G(1) phase were also observed at low concentrations (0.1 mu g / mL), which may be related to increased programmed cell death. Cytosine methylation profile analysis revealed cytosine hypermethylation at MWCNT-COOH concentrations of 1.0 and 10.0 mu g / mL and cytosine hypomethylation at MWCNT-COOH concentrations of 50.0 and 100.0 mu g / mL as compared to controls. We conclude that, in addition to cytogenotoxic effects, MWCNT-COOH alters cytosine methylation profiles and promotes root elongation.

Automated summary

Carbon nanotubes (CNTs) are important nanomaterials with various applications, but their increased production and use raise concerns about their potential impacts on the environment. In this study, we assessed the cytogenotoxic potential of carboxylated multi-walled carbon nanotubes (MWCNT-COOH) and their influence on the methylation patterns of Lactuca sativa meristematic cells. Our results showed that MWCNT-COOH induced root elongation at lower concentrations and decreased seed germination at higher concentrations. Cytogenetic analysis revealed increased chromosomal aberrations and micronucleus frequency, suggesting genotoxic effects. Additionally, MWCNT-COOH altered cytosine methylation profiles, with hypermethylation at lower concentrations and hypomethylation at higher concentrations.