Oxidative stress responses in different organs of carp (Cyprinus carpio) with exposure to ZnO nanoparticles

Changes in activities of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) and non-enzymatic antioxidant reduced glutathione (GSH) content and levels of Lipid peroxidation (LPO) in gill, liver, brain and intestine of juvenile carp (Cyprinus carpio) were evaluated after exposure to different concentrations (0.5, 5.0 and 50.0 mg/L) of waterborne nano-ZnO for 1, 3, 7, 10 and 14 day. The results showed that the variation trendency of antioxidant defense systems and LPO levels would be more significant with increasing concentration and exposure time. 50.0 mg/L nano-ZnO caused significant decrease of several enzymes activities and GSH content and increase of LPO level. As a result, these biomarkers were all appropriate for monitoring oxidative stress status of fish after exposure to nano-ZnO. Gill, liver and brain might be more sensitive response organs, being intestine the least altered organ. Further ecotoxicological evaluation should be made concerning the risk of nano-ZnO on aquatic environment.

► This paper was to investigate toxic effects on juvenile carp exposed to waterborne nano-ZnO. ► SOD, CAT, GPx activity and GSH content as well as LPO level were all appropriate for monitoring oxidative stress of fish after exposure to nano-ZnO. ► The variation of the biomarkers would be more significant with increasing concentration and time. ► Susceptibility to toxicity varied with organs of fish. Gill, liver and brain might be more sensitive organs, being intestine the least altered organ. ► Appropriate risk assessment should be made concerning nano-ZnO on aquatic ecosystem.