Silver nanoparticles disrupt regulation of steroidogenesis in fish ovarian cells

Despite the influx of silver nanoparticles (nAg) into the marine environment, their effects on fish reproduction remain completely unexplored. Using ovarian primary cells from marine medaka (Oryzias melastigma), in vitro studies were carried out to evaluate the effects of two differently coated nAg particles (Oleic Acid, (OA) nAg and Polyvinylpyrrolidone, (PVP) nAg) on fish ovarian tissues, using AgNO₃ as a positive control. Cytotoxicity was evaluated by MTT assay and expression of key genes regulating steroidogenesis (StAR, CYP 19a, CYP 11a, 3βHSD and 20βHSD) were determined by Q-RT-PCR. EC₅₀ values for PVP nAg, OA nAg and AgNO₃ were 7.25μgL^-1, 924.4μgL^-1, and 42.0μgL^-1 respectively, showing that toxicity of silver was greatly enhanced in the PVP coated nano-form. Down regulation of CYP 19a was observed in both nAg and AgNO₃ treatments, while down regulation of 3βHSD was only found in the OA nAg and AgNO₃ treatments. For the first time, our results demonstrated that nAg can affect specific genes regulating steroidogenesis, implicating nAg as a potential endocrine disruptor. Copyright © 2015 Elsevier B.V. All rights reserved.