The effects of nano-sized PbO on biomarkers of membrane disruption and DNA damage in a sub-chronic inhalation study on mice

Abstract

Although the production of engineered nanoparticles increases our knowledge of toxicity and mechanisms of bioactivity during relevant exposures is lacking. In the present study mice were exposed to PbO nanoparticles (PbONP; 192.5 µg/m³; 1.93 × 10⁶ particles/cm³) for 2, 5 and 13 weeks through continuous inhalation. The analyses addressed Pb and PbONP distribution in organs (lung, liver, kidney, brain) using electrothermal atomic absorption spectrometry and transmission electron microscopy, as well as histopathology and analyses of oxidative stress biomarkers. New LC-MS/MS methods were validated for biomarkers of lipid damage F2-isoprostanes (8-iso-prostaglandins F_2-alpha and E₂) and hydroxylated deoxoguanosine (8-OHdG, marker of DNA oxidation). Commonly studied malondialdehyde was also measured as TBARS by HPLC-DAD. The study revealed fast blood transport and distribution of Pb from the lung to the kidney and liver. A different Pb accumulation trend was observed in the brain, suggesting transfer of NP along the nasal nerve to the olfactory bulbs. Long-term inhalation of PbONP caused lipid peroxidation in animal brains (increased levels of TBARS and both isoprostanes). Membrane lipid damage was also detected in the kidney after shorter exposures, but not in the liver or lung. On the contrary, longer exposures to PbONP increased levels of 8-OHdG in the lung and temporarily increased lung weight after 2 and 5 weeks of exposure. The histopathological changes observed mainly in the lung and liver indicated inflammation and general toxicity responses. The present long-term inhalation study indicates risks of PbONP to both human health and the environment.

Keywords:

• Oxidative damage
• lead
• nanoparticle
• 8-OHdG
• TBARS
• 8-isoPGF2_α
• 8-isoPGE isoprostanes
• LC-MS/MS
• lipid peroxidation
• inhalation

Acknowledgments

The technical assistance of Ms. Monika Podborská is acknowledged.

Author contributions

Luc B validated and performed extractions and analyses of biomarkers of oxidative stress and genotoxicity, evaluated the results and prepared the manuscript. ZN contributed to the extractions and analyses of biomarkers of oxidative stress and data analyses, and also contributed to the writing of the manuscript. ZV designed and performed exposure experiments. LV performed collection of tissue samples, tissue processing analyses of the lead content in organs. BD analyzed lead in mice organs and nanoparticles. JD performed histological analyses. KK performed the exposure experiment and sampled nanoparticles. PM performed exposure experiment, measured nanoparticle concentration and evaluated the data. MB performed collection of tissue samples, histological analyses and interpretation of the data, and also contributed to the writing of the manuscript. AH contributed to histological analyses and finalizing the manuscript. KH contributed to the study design, interpretation of the data and to the writing of the manuscript. Lud B contributed to method development and study design, data processing and interpretation, writing of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was supported by the RECETOX Research Infrastructure grants LM2015051 and CZ.02.1.01/0.0/0.0/16_013/0001761 and by the Czech Science Foundation [grants No. P503/11/2315 and P503/12/G147].