Deposition trend of subchronic exposure of copper oxide nanoparticles (CuO-NPs) and its effect on the antioxidant system of Labeo rohita

Abstract

Copper oxide nanoparticles are used in various fields. The increased use also enhances the release of these particles into the aquatic environment. CuO-NPs cause toxicity to every stage of aquatic organisms’ lives. This study investigates the effects of CuO-NPs on the antioxidant system of rohu (Labeo rohita). Four treatment groups were maintained in this study including; T0 (control), T1 (0.5 µg/L), T2 (1 mµ/L) and T3 (1.5 mµ/L) CuO-NPs for 45 days. 25% of water was exchanged on daily basis with redosing with CuO-NPs. The samples were taken for antioxidant analysis after 45 days. The samples of gill, heart, liver and kidney were analyzed with graphite furnace atomic absorption spectroscopy to measure the absorbed concentration of Cu. Results showed an increase in Cu accumulation in tissues (P ≤ 0.001) in all the treatments compared to control. The accumulation pattern of Cu was gill > kidney > liver > heart. Besides, the treatment also disturbs the GST level in the liver, heart, kidney and gill tissue. A sharp decline in GST activities (P ≤ 0.05) was observed due to raised in MDA content. The high GSH level (P ≤ 0.001) in liver indicates an alteration in the defensive mechanism against. This study concluded that Cu has more potential to deposit in soft tissues from CuO-NPs and cause disruption in antioxidant defenses by raising the glutathione (GSH) level. This study recommended taking preventive measures for minimizing the entry of CuO-NPs into the aquatic environment and building up in the food chain.