In Vitro Co-Exposure to CeO2 Nanomaterials from Diesel Engine Exhaust and Benzo(a)Pyrene Induces Additive DNA Damage in Sperm and Cumulus Cells but Not in Oocytes.

Martina Cotena,Jeanne Perrin,Mélanie Auffan,Virginie Tassistro,Noémie Resseguier,Jérôme Rose

doi:10.3390/nano11020478

Abstract

Benzo(a)pyrene (BaP) is a recognized reprotoxic compound and the most widely investigated polycyclic aromatic hydrocarbon in ambient air; it is widespread by the incomplete combustion of fossil fuels along with cerium dioxide nanomaterials (CeO2 NMs), which are used in nano-based diesel additives to decrease the emission of toxic compounds and to increase fuel economy. The toxicity of CeO2 NMs on reproductive organs and cells has also been shown. However, the effect of the combined interactions of BaP and CeO2 NMs on reproduction has not been investigated. Herein, human and rat gametes were exposed in vitro to combusted CeO2 NMs or BaP or CeO2 NMs and BaP in combination. CeO2 NMs were burned at 850 °C prior to mimicking their release after combustion in a diesel engine. We demonstrated significantly higher amounts of DNA damage after exposure to combusted CeO2 NMs (1 µg·L−1) or BaP (1.13 µmol·L−1) in all cell types considered compared to unexposed cells. Co-exposure to the CeO2 NMs-BaP mixture induced additive DNA damage in sperm and cumulus cells, whereas no additive effect was observed in rat oocytes. This result could be related to the structural protection of the oocyte by cumulus cells and to the oocyte’s efficient system to repair DNA damage compared to that of cumulus and sperm cells.

Highlights

Diesel engines are one of many sources of ambient particulate matter and gaseous air pollutants [1]
The results are presented as the distribution of median values of olive tail moment (OTM) with 1st and 3rd quartiles obtained from three independent experiments
We investigated the potential interaction between aged CeO2 NMs and BaP and the consequential impact on reproductive cells

Summary

Introduction

Diesel engines are one of many sources of ambient particulate matter and gaseous air pollutants [1]. Diesel exhaust is a complex mixture of particles, commonly known as soot and gases and contains more than one hundred different organic and inorganic compounds, including many chemicals that have been designated as air pollutants [2]. Organization (WHO), upgraded the carcinogenicity of diesel emissions from Group 2 A (probably carcinogenic) to Group 1 (carcinogenic with sufficient evidence) [3]. Diesel engines are significant sources of polycyclic aromatic hydrocarbons (PAHs) in urban air [4]. Despite the hazards induced by PAHs to humans, there are no motor vehicle emission limits for these compounds in most countries.

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