Silver nanoparticle induced toxicity and cell death mechanisms in embryonic zebrafish cells

Cell death is the process that regulates homeostasis and biochemical changes in healthy cells. Silver nanoparticles (AgNPs) act as powerful cell death inducers through the disruption of cellular signalling functions. In this study, embryonic zebrafish cells (ZF4) were used as a potential early-stage aquatic model to evaluate the molecular and cell death mechanisms implicated in the toxicity of AgNPs and Ag+. Here, a low, medium, and high concentration (2.5, 5, and 10 mu g mL(-1)) of three different sizes of AgNPs (10, 30 and 100 nm) and ionic Ag+ (1, 1.5 and 2 mu g mL(-1)) were used to investigate whether the size of the nanomaterial, ionic form, and mass concentration were related to the activation of particular cell death mechanisms and/or induction of different signalling pathways. Changes in the physicochemical properties of the AgNPs were also assessed in the presence of complex medium (cell culture) and reference testing medium (ultra-pure water). Results demonstrated that AgNPs underwent dissolution, as well as changes in hydrodynamic size, zeta potential and polydispersity index in both tested media depending on particle size and concentration. Similarly, exposure dose played a key role in regulating the different cell death modalities (apoptosis, necrosis, autophagy), and the signalling pathways (repair mechanisms) in cells that were activated in the attempt to overcome the induced damage. This study contributes to the 3Rs initiative to replace, reduce and refine animal experimentation through the use of alternative models for nanomaterials assessment.

Automated summary

Cell death is a crucial process in maintaining cell homeostasis, and silver nanoparticles (AgNPs) have been shown to induce cell death by disrupting cellular signaling functions. This study used embryonic zebrafish cells as a model to investigate the mechanisms involved in AgNPs and Ag+ toxicity, with different sizes and concentrations of AgNPs and Ag+ being tested. The results indicated that exposure dose and physicochemical properties of AgNPs played a significant role in regulating various cell death modalities and signaling pathways in response to induced damage.