Investigations of the nervous system biomarkers in the brain and muscle of freshwater fish (Oreochromis niloticus) following accumulation of nanoparticles in the tissues

Abstract

The use of nanoparticles (NPs) has increased in recent years and consequently they are being released into the environment.The final destination of most NPs is the aquatic environment due to washing up by rain waters. Fish (n = 120) were exposed to differentconcentrations (0, 1, 5, and 25 mg/L) of aluminum-oxide (Al2O3), copper-oxide (CuO), and titanium-dioxide (TiO2) NPs for 14 daysand 14 days of depuration period (no NP in water). Following NP exposures, activities of Na,K-ATPase, Mg-ATPase, Ca-ATPase, andacetylcholinesterase (AChE) in the brain and muscle were measured. AChE activity in the brain and muscle decreased significantly (P 0.05) alteration. Similarly,Ca-ATPase activity in the muscle was decreased significantly by Al2O3 NPs and CuO NPs, but not by TiO2 NPs. Total ATPase andMg-ATPase activities did not alter significantly in the brain, though Na,K-ATPase activity decreased after exposure to CuO NPs. Half(n = 60) of the NP-exposed fish were transferred to NP-free waters for depuration experiments for 14 days. Transmission electronmicroscope images demonstrated NP aggregates in the tissues, although some NPs were retained in the tissues after the depuration. Thisstudy showed that NPs are able to alter nervous system biomarkers, copper NP being the most effective one.