Acute exposition to Roundup Transorb® induces systemic oxidative stress and alterations in the expression of newly sequenced genes in silverside fish (Odontesthes humensis).

Roundup Transorb® (RDT) is a glyphosate-based herbicide commonly used in agricultural practices worldwide. This herbicide exerts negative effects on the aquatic ecosystem and affects bioenergetic and detoxification pathways, oxidative stress, and cell damage in marine organisms. These effects might also occur at the transcriptional level; however, the expression of genes associated with oxidative stress has not been studied well. Odontesthes humensis is a native Brazilian aquatic species naturally distributed in the habitats affected by pesticides, including Roundup Transorb® (RDT). This study evaluated the toxic effects of short-term exposure to RDT on O. humensis. Moreover, the genes related to oxidative stress were sequenced and characterized, and their expressions in the gills, hepatopancreas, kidneys, and brain of the fish were quantified by quantitative reverse transcription-polymerase chain reaction. The animals were exposed to two environmentally relevant concentrations of RDT (2.07 and 3.68 mg L-1) for 24 h. Lipid peroxidation, reactive oxygen species (ROS), DNA damage, and apoptosis in erythrocytes were quantified by flow cytometry. The expression of the target genes was modulated in most tissues in the presence of the highest tested concentration of RDT. In erythrocytes, the levels of lipid peroxidation, ROS, and DNA damage were increased in the presence of both the concentrations of RDT, whereas cell apoptosis was increased in the group exposed to 3.68 mg L-1 RDT. In conclusion, acute exposure to RDT caused oxidative stress in the fish, induced negative effects on cells, and modulated the expression of genes related to the enzymatic antioxidant system in O. humensis.