Oxidative Stress-Mediated Apoptosis and Genotoxicity Induced by Silver Nanoparticles in Freshwater Snail Lymnea luteola L.

Silver is one of the most toxic metals to freshwater aquatic organisms. Limited efforts have been made to study apoptosis and genotoxic potential of silver nanoparticles (AgNPs) in freshwater snail Lymnea luteola L. (L. luteola). Therefore, the present investigation was aimed to study the induction of apoptosis and DNA damage by AgNPs in L. luteola. AgNPs showed molluscicidal activity against L. luteola and three concentrations of AgNPs were selected, the concentration I (4 mu g/l), concentration II (12 mu g/l), and the concentration III (24 mu g/l). Induction of oxidative stress in snail hemolymph was observed by a decrease in reduced glutathione (GSH) and glutathione S-transferase (GST) levels at different concentration of AgNPs, and on the other hand, malondialdehyde (MDA) levels increased at lower concentrations but decreased in higher concentration of AgNPs. Catalase (CAT) activity was also decreased at lower concentrations and increased in higher concentration of AgNPs. Flow cytometry data showed that AgNPs exposed hemocyte cells promote apoptotic and necrotic-mediated cell death when AgNPs concentrations were 12 and 24 mu g/l compared to control. DNA damage scores increased with the exposure levels of AgNPs, and dose- and time-dependent effects were observed. A significant positive correlation was observed among reactive oxygen species (ROS) generation, apoptosis, and DNA damage. The study suggests that ROS may be involved in inducing apoptosis and DNA damage in the AgNPs exposed hemocyte cells of L. luteola. This study demonstrates that AgNPs is lethal to freshwater snail L. luteola.