Glyphosate and glyphosate-based herbicides induce Poecilia reticulata to maintain redox equilibrium during and after coexposure to iron oxide nanoparticles (y-Fe2O3)

Abstract

Iron oxide nanoparticles (IONPs) are being increasingly recognized as viable materials for environmental remediation due to their capacity to adsorb contaminants such as glyphosate (GLY) on their surfaces. Nevertheless, the ecotoxicological implications of IONPs associated with GLY necessitate thorough evaluation to ascertain the safety of such remediation strategies. In this context, the present investigation was conducted to examine hepatic biomarkers pertinent to the redox system, as well as ultrastructural hepatic alterations in Poecilia reticulata, following a 21-day exposure to environmentally relevant concentrations of IONPs, iron ions (Fe), and glyphosate in its pure form (GLY) as well as a commercial glyphosate-based herbicide (GBH). After this exposure, the fish underwent a 21-day recovery in uncontaminated water. The results indicated an increase in the activity of catalase (CAT) and glutathione S-transferase (GST) and in the concentration of glutathione (GSH) in the animals subjected to IONP+GBH and IONP+GLY treatments. This biochemical response persisted for the duration of both the exposure and recovery phases. Concurrently, hepatocytes displayed mitochondria with increased electron density, augmented lipid droplet accumulation, and expanded necrotic areas within the hepatic tissue. In contrast, fish exposed solely to IONPs exhibited sustained redox homeostasis throughout the investigative timeline. These findings suggest that the coexposure toxicity of IONP+GLY and IONP+GBH is attributable to the agent adsorbed onto the IONPs and that P. reticulata could maintain an active antioxidant defense mechanism throughout the entire study period.