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, CYP19a, CYP11a, 3 beta HSD and 20 beta HSD) were determined by Q-RT-PCR. EC50 values for PVP nAg, OA nAg and AgNO3 were 7.25 mu g L-1, 924.4 mu g L-1, and 42.0 mu g L-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 3 beta HSD 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. (C) 2015 Elsevier B.V. All rights reserved.