Abstrakt
Many experimental studies have demonstrated the ability of nanoparticles to induce DNA damage and oxidative stress in a number of organs, probably due to the formation of reactive oxygen species. Our knowledge, however, is still limited, especially as regards the persistence of genotoxic effects after long-term exposure to nanoparticles and their health risks.
We decided, therefore, to analyze DNA damage in lymphocytes of workers long-term exposed to nanoparticles due to processing of nanocomposite materials. Exposed group involved 20 employees examined pre-shift and post-shift, samples from 20 controls were taken in the morning.
Lymphocytes were isolated from heparinized blood on a ficoll gradient and frozen until further processing. An alkaline comet assay with enzymes of excision DNA repair (Fpg and Endo III) was used to detect DNA damage.
Within the exposed group, the values of total DNA damage in post-shift samples slightly exceed those in pre-shift ones, but the difference was not statistically significant (% tail DNA 4.47 +/- 1.43 vs 3.95 +/- 1.23, respectively). Compared to controls, however, the workers showed significantly higher levels of genotoxic damage, both in terms of DNA breakage (% tail DNA 3.08 +/- 1.04 vs 1.63 +/- 0.50, respectively; p<0.0001), and oxidized bases (% tail DNA 0.88 +/- 0.41 vs. 0.57 +/- 0.25, respectively; p < 0.01).
Our preliminary results thus indicate that long term occupational exposure to nanoparticles is associated with an increased risk of DNA damage.