Silver nanoparticles have protein-specific negative impacts on cardiac function in brook trout (Salvelinus fontinalis)

Abstract

Silver nanoparticles (nAg) have been increasingly prevalent in societal use due to their antimicrobial nature, highly diversifiable structure, and small size. Non-exhaustively, they are being used in textiles, toys, cleaning products, and other technologies before being released into the environment at various stages of production. With the increasing use of nAg in consumer products, potential long-term effects on humans and the aquatic environment are a serious concern. This study looked to characterize the cardiac effects of nAg in brook trout. The nAg exposure through intravascular (I.V.) injection, 700μg/kg, resulted in a significant increase in both heart rate and blood pressure. There was also a decrease in Na+/K+ ATPase function seen in heart tissue. Inhibition of Na+/K+ ATPase could have indirectly led to the decrease in Na+/Ca2+ exchange, increasing localized Ca2+ and thereby increasing contractility. The total membrane ATPase was not affected, therefore the mechanism of this inhibition of Na+/K+ ATPase is likely enzyme specific. in the nAg treatment groups, propranolol and atropine were not able to induce an effect on heart rate. This could be due to nAg binding to β-adrenergic, or cholinergic receptor sites prior to harmacological intervention. These results indicate that nAg have a negative impact on cardiac function in brook trout, however further research is required to characterize the mechanism of toxicity.