Potential toxic effects of titanium oxide (TiO2) nanoparticles on the biological, biochemical, and histological aspects of the land snail Helix aspersa.

Nanotechnology has come a long way in our lives. However, it maintains some negative effects on the environment. This study aims to use the land snail Helix aspersa as a bioindicator. Titanium dioxide nanoparticles (TiO2NPs) had been used at 70 and 140 µg/L for two weeks by the spraying method. The oxidative biomarkers, condition index (CI), DNA damage, hemocyte count, and phagocytic activity were estimated. The toxicity of TiO2NPs was determined (LC50 = 544 µg/L). The exposure to TiO2NPs caused a significant reduction of the activities of superoxide dismutase (SOD) and catalase (CAT) in the digestive gland of Helix aspersa (the activity of CAT was 3.4 ± 0.1 (P = 0.001), SOD was 11 ± 1 (P = 0.0002) at concentration 140 µg/L after two weeks). The activity of glutathione peroxidase (GPX) was (1.13 ± 0.01 µ/mg protein at 140 µg/L compared with controls (5.47 ± 0.01 µ/mg protein). The treatment caused DNA damage in the hemocytes (tail DNA % = 8.66 ± 0.02 and tail moment = 52.99 ± 0 at140 µg/L (P = 0.002)). In the digestive gland, both tail DNA % and tail moment increased (tail moment = 78.38 ± 0.08 compared with control = 2.29 ± 0.09 (P = 0.0001)). The total count of hemocytes significantly decreased after two weeks (the average number was 71 ± 1.5 compared with controls 79 ± 1.1 at 140 µg/L). Furthermore, TiO2NPs caused histological alterations in the digestive gland of Helix aspersa. It can be concluded that the Helix aspersa can be used as environmental pollution bioindicator. A comprehensive evaluation of toxic effects induced by TiO2NPs in vivo assays must be investigated.

Oxidative stress and histopathological effect of zinc oxide nanoparticles on the garden snail Helix aspersa.

Nanoparticles have many applications in medicine and biology but they have adverse toxic effects on the biosystem. Therefore, this study aimed to evaluate the toxicity of zinc nanoparticles (ZnO NPs) on the garden snail Helix aspersa. ZnO NPs were used at different concentrations for 7 days. The biomarkers of the oxidative stress and histopathology of the hepatopancreas were estimated. ZnO NPs significantly (p ≤ 0.05) increased catalase (CAT) with time- and concentration-dependent manner. Glutathione S-transferase (GST) activity was significantly (p ≤ 0.05) increased at the concentrations 35 µg/ml and 45 µg/ml after 1 and 3 days of exposure. The present results recorded also a significant elevation in malondialdehyde (MDA) level (time-/concentration-dependent), it was 3.2 ± 0.1, at concentration 45 µg/ml. ZnO NPs induced significant decrease in glutathione (GSH) content (8.7 ± 0.2 at 45 µg/ml) (p ≤ 0.05) at 7 days. Moreover, ZnO NPs induced histopathological alterations in the digestive gland of Helix aspersa. From these results, such biochemical and histopathological alterations in Helix aspersa is a suitable bioindicator of nanoecotoxicological effects.