Toxicological effect of exposure to different doses of zinc oxide nanoparticles on brain and heart structures of male Wistar rats.

Abstract

Nanotechnology is rapidly developing in the fields of industry, medicine and nutrition. The aim of this study was to evaluate the effect of zinc oxide nanoparticles (ZnO Nps) toxicity on rats’ heart and brain. Eighty Wistar male rats were allotted into eight groups: control group, sham group receiving 0.9% normal saline and six treatment groups receiving ZnO Nps (4, 8, 25, 50, 100 and 200 mg/kg) intraperitoneally twice a week over 28 days. For behavioural evaluation, shuttle box and Y-maze tests were done. The heart and brain structures were obtained for bioaccumulation, histopathological exa­mination and biochemical analysis. Histopathologic lesions in the heart structures of 200 mg/kg ZnO Nps group included necrosis, hyperaemia, and vacuolar degeneration. In brain structures, changes included necrosis, gliosis and spongiform change. Serum levels of creatine phosphokinase (CPK) in the treated groups showed an increase compared to the control group. The accumulation of nanoparticles has also shown a dose-dependent increase in the heart and brain. Moreover, there was a significant difference between the control group and the 200 mg/kg group (P<0.05). The mean acquisition of the passive avoidance test showed a significant decrease in the 200 mg/kg group compared to the control group (P<0.05). The alternation behaviour test differed significantly between the 100 and 200 mg /kg groups with other groups (P<0.05). The results indicated that zinc nanoparticles at doses more than 25 mg/kg were related to heart and brain toxicity in the form of increased bioaccumulation, malondialdehyde (MDA), histopathological lesions and CPK and decrease in behaviour index, glutathione peroxidase (GPx), superoxide dismutase (SOD) and ferric reducing antioxidant power (FRAP).