effect of sub acute exposure of nano zinc particles on oxidative stress parameters in rats

Background: zinc (zn) is one of the most important essential elements in the body of animals and plants. zinc plays a significant role in the structure of more than 300 different proteins and in many life supporting biochemical and metabolic processes such as cellular respiration and protection against free radicals. nanoparticles of zinc are the new form of zinc used in cosmetic and personal care products and also in livestock feed and food packaging. objectives: the aim of this study was to evaluate the effects of several sizes and doses of zinc nanoparticles on antioxidant defense system in rat compared to controls. methods: zinc nanoparticles (10, 20 and 30 nm) at 3 doses (3, 10 and 100 mg/kg bw) were administrated orally for 28 days among 9 experimental groups (n=5). one experimental group was treated orally with zncl2 (100 mg/kg bw) for 28 days and control group received normal saline (n=5). after 28 days, the rat was decapitated and serum was separated from the blood samples. the ferric reducing ability of plasma (frap), thiobarbituric acid reactive substances (tbars) and activity of glutathione peroxidase (gpx), and superoxide dismutase (sod) enzymes in serum samples were measured as biomarkers of oxidative stress and compared with control group. results: this survey showed that zinc nanoparticles cause induction of gpx and sod activity (p<0.05) and also increased the level of tbars (p<0.05). this assay also showed zinc nanoparticles cause significant decrease in total antioxidant activity of plasma (frap) (p<0.001). conclusions: nano zinc induced oxidative stress in a dose dependent manner in large sizes, while their effects depend on the level of ionization in small sizes.