Potential toxic effects of titanium dioxide nanoparticles and carbon nanotubes on land snail Helix aspersa: use of oxidative stress as a reliable biomarker for ecotoxicology assessment

Abstract

Oxidative stress represents a main regularly informed mechanism of nanoparticles (NPs) toxicity. The present work was designed to evaluate the oxidative stress in haemolymph and digestive gland of snail Helix aspersa after exposure to different dermal doses: 10.8 and 2.17 µg snail^-1 for titanium dioxide nanoparticles (TiO₂NPs), and 8.0 and 1.6 µg snail^-1 for Single-Walled Carbon Nanotubes (SWCNTs) during 48 h. The results indicated that, both nanomaterials (NMs) induced significant increases in malondialdehyde (MDA) as biomarker for lipid peroxidation (LPO). However, SWCNTs induced significant decline in reduced glutathione (GSH) content compared with the control. Catalase (CAT) activity significantly increased for the all treatments greater than the control. On the other hand, activities of glutathione-S-transferase (GST) and glutathione peroxidase (GPx) slightly decreased for both NMs. Nanoparticles (NPs) of TiO₂ increased activity of glutathione reductase (GR) in both haemolymph and digestive gland homogenates, while SWCNTs treatments exhibited activities did not exceed the value of the control (0.08 U mg^-1 protein). The present findings indicate that, alterations of antioxidant enzymes activity and levels of MDA and GSH are recognized to oxidative stress. Consequently, the use of snail, H. aspersa can offer a respectable sentinel model to assess ecotoxicological effects of NMs on the gastropods.