Roundup(®) in Zebrafish: Effects on Oxidative Status and Gene Expression

The objective of the present study was to determine the effects of Roundup on oxidative status in adult Danio rerio liver and gills. Reactive oxygen species (ROS) and antioxidant capacity (ACAP) were measured in fish after exposure to Roundup (5 and 10 mg/L) for 24, 48, 72, and 96 h. Furthermore, gene expression related to antioxidant response was evaluated after 24 and 96 h. In gills, an increase in ACAP was observed after 96 h in the highest concentration. In the liver, a reduction in ROS and ACAP was observed after 24 h, whereas an increase in ACAP was observed after 48 h in the highest concentration. Exposure to the lowest concentration caused a reduction in ROS after 72 and 96 h. Regarding gene expression, a reduction in superoxide dismutase 2 (sod2) and glutathione S-transferase (gstπ) was observed. An increase in uncoupling protein 1 (ucp1) expression was observed in gills of animals exposed to the highest concentration after 24 h. Glutathione peroxidase (gpx) gene expression was reduced in the gills of animals exposed to the lowest concentration; however, it was induced in liver tissue after 96 h of exposure to the highest concentration. These results indicate that zebrafish exposure to Roundup alters oxidative status and causes a response in terms of antioxidant defense system gene expression.

Effects of the herbicide Roundup on the polychaeta Laeonereis acuta: Cholinesterases and oxidative stress

Glyphosate based herbicides, including Roundup, are widely employed in agriculture and urban spaces. The objective of this study was to evaluate the toxicological effects of Roundup on the estuarine polychaeta Laeonereis acuta. Biomarkers of oxidative stress as well as acetylcholinesterase and propionilcholinesterase activities were analyzed. Firstly, the LC50 96h for L. acuta was established (8.19mg/L). After, the animals were exposed to two Roundup concentrations: 3.25mg/L (non-observed effect concentration - NOEC) and 5.35mg/L (LC10) for 24h and 96h. Oxygen consumption was determined and the animals were divided into three body regions (anterior, middle and posterior) for biochemical analysis. An inhibition of both cholinesterase isoforms were observed in animals exposed to both Roundup concentrations after 96h. A significant reactive oxygen species (ROS) reduction was observed in the posterior region of animals in both periods, while antioxidant capacity against peroxyl radicals (ACAP) was reduced in the posterior region of animals exposed for 24h. Considering the antioxidant defense system, both GSH levels and enzyme activities (catalase, superoxide dismutase, glutathione s-transferase, glutathione peroxidase and glutamate cysteine ligase) were not altered after exposure. Lipid peroxidation was reduced in all analyzed body regions in both Roundup concentrations after 24h. Animals exposed to the highest concentration presented a reduction in lipid peroxidation in the anterior region after 96h, while animals exposed to the lowest concentration presented a reduction in the middle region. Overall results indicate that Roundup exposure presents toxicity to L. acuta, causing a disruption in ROS and ACAP levels as well as affects the cholinergic system of this invertebrate species.