Assesment of nanoparticles of TiO2 on behavioral and nervous system statuts of Wistar rats

Abstract

Titanium dioxide is a constituent widespread in nature and widely used by man as a food additive, pigments and catalysts. This work concerns the evaluation of the potential toxicity of titanium dioxide nanoparticles (TiO2) at different doses on the nervous system in Wistar rats which are perfectly suited to toxicological studies to easily assess the toxicity of a xenobiotic. The rats were exposed to 1.25ml/kg/d and 2.5ml/kg/d of nano- TiO2 during a treatment period of 90 days. The study was carried out for 90 days on 18 rats divided into three groups (6 rats in each): (i) a control group, (ii) a group treated with titanium dioxide (2.5 ml/kg/day), ( iii) a group treated with titanium dioxide (1.25 ml/kg/d). The relative weight of the brain, the concentration of encephalic metabolites: proteins, lipids and carbohydrates also on the enzymatic and non-enzymatic parameters (MDA, GSH, CAT, GPx, GST) and with behavioral studies have been used as biomarkers of neurotoxicity. The biochemical study revealed a disturbance of the main macromolecules namely; proteins, carbohydrates, lipids and this in parallel with an inhibition of body growth (reduction of body and relative weight) Concerning the enzymatic activities our results show that TiO2 decrease the level of enzymatic activities (GST, GPx, CAT) for the non-enzymatic parameters we showed an increase in the level of MDA, the lipid peroxidation index, and a decrease in GSH . On the other hand, we also highlighted changes in the psychic behavior of the rats which were manifested by cases of anxiety, disturbance of memory and learning. Our results show that the presence of metallic TiO2 nanoparticles causes various disturbances of biomarkers; which confirms the toxic nature of TiO2 nanoparticles at the dose studied on the nervous system.